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Triangle - Viquipèdia, l'enciclopèdia lliure

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skin-vector-search-vue mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject mw-editable page-Triangle rootpage-Triangle skin-vector-2022 action-view"><a class="mw-jump-link" href="#bodyContent">Vés al contingut</a> <div class="vector-header-container"> <header class="vector-header mw-header"> <div class="vector-header-start"> <nav class="vector-main-menu-landmark" aria-label="Lloc"> <div id="vector-main-menu-dropdown" class="vector-dropdown vector-main-menu-dropdown vector-button-flush-left vector-button-flush-right" > <input type="checkbox" id="vector-main-menu-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-main-menu-dropdown" class="vector-dropdown-checkbox " aria-label="Menú principal" > <label id="vector-main-menu-dropdown-label" for="vector-main-menu-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-menu mw-ui-icon-wikimedia-menu"></span> <span class="vector-dropdown-label-text">Menú principal</span> </label> <div class="vector-dropdown-content"> <div id="vector-main-menu-unpinned-container" class="vector-unpinned-container"> <div id="vector-main-menu" class="vector-main-menu vector-pinnable-element"> <div class="vector-pinnable-header vector-main-menu-pinnable-header vector-pinnable-header-unpinned" data-feature-name="main-menu-pinned" data-pinnable-element-id="vector-main-menu" data-pinned-container-id="vector-main-menu-pinned-container" data-unpinned-container-id="vector-main-menu-unpinned-container" > <div class="vector-pinnable-header-label">Menú principal</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-main-menu.pin">mou a la barra lateral</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-main-menu.unpin">amaga</button> </div> <div id="p-navigation" class="vector-menu mw-portlet mw-portlet-navigation" > <div class="vector-menu-heading"> Navegació </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-mainpage-description" class="mw-list-item"><a href="/wiki/Portada" title="Visiteu la pàgina principal [z]" accesskey="z"><span>Portada</span></a></li><li id="n-randompage" class="mw-list-item"><a href="/wiki/Especial:Article_aleatori" title="Carrega una pàgina a l’atzar [x]" accesskey="x"><span>Article a l'atzar</span></a></li><li id="n-Articles-de-qualitat" class="mw-list-item"><a href="/wiki/Viquip%C3%A8dia:Articles_de_qualitat"><span>Articles de qualitat</span></a></li> </ul> </div> </div> <div id="p-Comunitat" class="vector-menu mw-portlet mw-portlet-Comunitat" > <div class="vector-menu-heading"> Comunitat </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-portal" class="mw-list-item"><a href="/wiki/Viquip%C3%A8dia:Portal" title="Sobre el projecte, què podeu fer, on trobareu les coses"><span>Portal viquipedista</span></a></li><li id="n-Agenda-d&#039;actes" class="mw-list-item"><a href="/wiki/Viquip%C3%A8dia:Trobades"><span>Agenda d'actes</span></a></li><li id="n-recentchanges" class="mw-list-item"><a href="/wiki/Especial:Canvis_recents" title="Una llista dels canvis recents al wiki [r]" accesskey="r"><span>Canvis recents</span></a></li><li id="n-La-taverna" class="mw-list-item"><a href="/wiki/Viquip%C3%A8dia:La_taverna"><span>La taverna</span></a></li><li id="n-contactpage" class="mw-list-item"><a href="/wiki/Viquip%C3%A8dia:Contacte"><span>Contacte</span></a></li><li id="n-Xat" class="mw-list-item"><a href="/wiki/Viquip%C3%A8dia:Canals_IRC"><span>Xat</span></a></li><li id="n-help" class="mw-list-item"><a href="/wiki/Viquip%C3%A8dia:Ajuda" title="El lloc per a saber més coses"><span>Ajuda</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> <a href="/wiki/Portada" class="mw-logo"> <img class="mw-logo-icon" src="/static/images/icons/wikipedia.png" alt="" aria-hidden="true" height="50" width="50"> <span class="mw-logo-container skin-invert"> <img class="mw-logo-wordmark" alt="Viquipèdia" src="/static/images/mobile/copyright/wikipedia-wordmark-ca.svg" style="width: 7.5em; height: 1.4375em;"> <img class="mw-logo-tagline" alt="l&#039;Enciclopèdia Lliure" src="/static/images/mobile/copyright/wikipedia-tagline-ca.svg" width="120" height="14" style="width: 7.5em; height: 0.875em;"> </span> </a> </div> <div class="vector-header-end"> <div id="p-search" role="search" class="vector-search-box-vue vector-search-box-collapses vector-search-box-show-thumbnail vector-search-box-auto-expand-width vector-search-box"> <a href="/wiki/Especial:Cerca" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only search-toggle" title="Cerca a la Viquipèdia 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</div> <nav class="vector-user-links vector-user-links-wide" aria-label="Eines personals"> <div class="vector-user-links-main"> <div id="p-vector-user-menu-preferences" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-userpage" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <nav class="vector-appearance-landmark" aria-label="Aparença"> <div id="vector-appearance-dropdown" class="vector-dropdown " title="Change the appearance of the page&#039;s font size, width, and color" > <input type="checkbox" id="vector-appearance-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-appearance-dropdown" class="vector-dropdown-checkbox " aria-label="Aparença" > <label id="vector-appearance-dropdown-label" for="vector-appearance-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-appearance mw-ui-icon-wikimedia-appearance"></span> <span class="vector-dropdown-label-text">Aparença</span> </label> <div class="vector-dropdown-content"> <div id="vector-appearance-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div id="p-vector-user-menu-notifications" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-overflow" class="vector-menu mw-portlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="//donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&amp;utm_medium=sidebar&amp;utm_campaign=C13_ca.wikipedia.org&amp;uselang=ca" class=""><span>Donatius</span></a> </li> <li id="pt-createaccount-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Especial:Crea_compte&amp;returnto=Triangle" title="Us animem a crear un compte i iniciar una sessió, encara que no és obligatori" class=""><span>Crea un compte</span></a> </li> <li id="pt-login-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Especial:Registre_i_entrada&amp;returnto=Triangle" title="Us animem a registrar-vos, però no és obligatori [o]" accesskey="o" class=""><span>Inicia la sessió</span></a> </li> </ul> </div> </div> </div> <div id="vector-user-links-dropdown" class="vector-dropdown vector-user-menu vector-button-flush-right vector-user-menu-logged-out" title="Més opcions" > <input type="checkbox" id="vector-user-links-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-user-links-dropdown" class="vector-dropdown-checkbox " aria-label="Eines personals" > <label id="vector-user-links-dropdown-label" for="vector-user-links-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-ellipsis mw-ui-icon-wikimedia-ellipsis"></span> <span class="vector-dropdown-label-text">Eines personals</span> </label> <div class="vector-dropdown-content"> <div id="p-personal" class="vector-menu mw-portlet mw-portlet-personal user-links-collapsible-item" title="Menú d&#039;usuari" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport" class="user-links-collapsible-item mw-list-item"><a href="//donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&amp;utm_medium=sidebar&amp;utm_campaign=C13_ca.wikipedia.org&amp;uselang=ca"><span>Donatius</span></a></li><li id="pt-createaccount" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Especial:Crea_compte&amp;returnto=Triangle" title="Us animem a crear un compte i iniciar una sessió, encara que no és obligatori"><span class="vector-icon mw-ui-icon-userAdd mw-ui-icon-wikimedia-userAdd"></span> <span>Crea un compte</span></a></li><li id="pt-login" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Especial:Registre_i_entrada&amp;returnto=Triangle" title="Us animem a registrar-vos, però no és obligatori [o]" accesskey="o"><span class="vector-icon mw-ui-icon-logIn mw-ui-icon-wikimedia-logIn"></span> <span>Inicia la sessió</span></a></li> </ul> </div> </div> <div id="p-user-menu-anon-editor" class="vector-menu mw-portlet mw-portlet-user-menu-anon-editor" > <div class="vector-menu-heading"> Pàgines per a editors no registrats <a href="/wiki/Ajuda:Introducci%C3%B3" aria-label="Vegeu més informació sobre l&#039;edició"><span>més informació</span></a> </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-anoncontribs" class="mw-list-item"><a href="/wiki/Especial:Contribucions_pr%C3%B2pies" title="Una llista de les modificacions fetes des d&#039;aquesta adreça IP [y]" accesskey="y"><span>Contribucions</span></a></li><li id="pt-anontalk" class="mw-list-item"><a href="/wiki/Especial:Discussi%C3%B3_personal" title="Discussió sobre les edicions per aquesta adreça ip. [n]" accesskey="n"><span>Discussió per aquest IP</span></a></li> </ul> </div> </div> </div> </div> </nav> </div> </header> </div> <div class="mw-page-container"> <div class="mw-page-container-inner"> <div class="vector-sitenotice-container"> <div id="siteNotice"><!-- CentralNotice --></div> </div> <div class="vector-column-start"> <div class="vector-main-menu-container"> <div id="mw-navigation"> <nav id="mw-panel" class="vector-main-menu-landmark" aria-label="Lloc"> <div id="vector-main-menu-pinned-container" class="vector-pinned-container"> </div> </nav> </div> </div> <div class="vector-sticky-pinned-container"> <nav id="mw-panel-toc" aria-label="Contingut" data-event-name="ui.sidebar-toc" class="mw-table-of-contents-container vector-toc-landmark"> <div id="vector-toc-pinned-container" class="vector-pinned-container"> <div id="vector-toc" class="vector-toc vector-pinnable-element"> <div class="vector-pinnable-header vector-toc-pinnable-header vector-pinnable-header-pinned" data-feature-name="toc-pinned" data-pinnable-element-id="vector-toc" > <h2 class="vector-pinnable-header-label">Contingut</h2> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-toc.pin">mou a la barra lateral</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">amaga</button> </div> <ul class="vector-toc-contents" id="mw-panel-toc-list"> <li id="toc-mw-content-text" class="vector-toc-list-item vector-toc-level-1"> <a href="#" class="vector-toc-link"> <div class="vector-toc-text">Inici</div> </a> </li> <li id="toc-Història" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Història"> <div class="vector-toc-text"> <span class="vector-toc-numb">1</span> <span>Història</span> </div> </a> <ul id="toc-Història-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Tipus_de_triangles" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Tipus_de_triangles"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Tipus de triangles</span> </div> </a> <button aria-controls="toc-Tipus_de_triangles-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Commuta la subsecció Tipus de triangles</span> </button> <ul id="toc-Tipus_de_triangles-sublist" class="vector-toc-list"> <li id="toc-Classificació_segons_els_costats" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Classificació_segons_els_costats"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1</span> <span>Classificació segons els costats</span> </div> </a> <ul id="toc-Classificació_segons_els_costats-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Classificació_segons_els_angles" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Classificació_segons_els_angles"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2</span> <span>Classificació segons els angles</span> </div> </a> <ul id="toc-Classificació_segons_els_angles-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Punts,_línies_i_cercles_associats_a_un_triangle" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Punts,_línies_i_cercles_associats_a_un_triangle"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Punts, línies i cercles associats a un triangle</span> </div> </a> <button aria-controls="toc-Punts,_línies_i_cercles_associats_a_un_triangle-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Commuta la subsecció Punts, línies i cercles associats a un triangle</span> </button> <ul id="toc-Punts,_línies_i_cercles_associats_a_un_triangle-sublist" class="vector-toc-list"> <li id="toc-Mitjanes_i_centre_de_gravetat" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Mitjanes_i_centre_de_gravetat"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1</span> <span>Mitjanes i centre de gravetat</span> </div> </a> <ul id="toc-Mitjanes_i_centre_de_gravetat-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Mediatrius_i_circumferència_circumscrita" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Mediatrius_i_circumferència_circumscrita"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.2</span> <span>Mediatrius i circumferència circumscrita</span> </div> </a> <ul id="toc-Mediatrius_i_circumferència_circumscrita-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Bisectrius_i_circumferència_inscrita" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Bisectrius_i_circumferència_inscrita"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.3</span> <span>Bisectrius i circumferència inscrita</span> </div> </a> <ul id="toc-Bisectrius_i_circumferència_inscrita-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Altures_i_ortocentre" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Altures_i_ortocentre"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.4</span> <span>Altures i ortocentre</span> </div> </a> <ul id="toc-Altures_i_ortocentre-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Recta_i_cercle_d&#039;Euler" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Recta_i_cercle_d&#039;Euler"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.5</span> <span>Recta i cercle d'Euler</span> </div> </a> <ul id="toc-Recta_i_cercle_d&#039;Euler-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Superfície" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Superfície"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Superfície</span> </div> </a> <button aria-controls="toc-Superfície-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Commuta la subsecció Superfície</span> </button> <ul id="toc-Superfície-sublist" class="vector-toc-list"> <li id="toc-Fent_servir_vectors" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Fent_servir_vectors"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.1</span> <span>Fent servir vectors</span> </div> </a> <ul id="toc-Fent_servir_vectors-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Aplicant_trigonometria" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Aplicant_trigonometria"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.2</span> <span>Aplicant trigonometria</span> </div> </a> <ul id="toc-Aplicant_trigonometria-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Fent_servir_coordenades" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Fent_servir_coordenades"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.3</span> <span>Fent servir coordenades</span> </div> </a> <ul id="toc-Fent_servir_coordenades-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Fent_servir_la_fórmula_d&#039;Heró" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Fent_servir_la_fórmula_d&#039;Heró"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.4</span> <span>Fent servir la fórmula d'Heró</span> </div> </a> <ul id="toc-Fent_servir_la_fórmula_d&#039;Heró-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Propietats_dels_triangles" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Propietats_dels_triangles"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Propietats dels triangles</span> </div> </a> <button aria-controls="toc-Propietats_dels_triangles-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Commuta la subsecció Propietats dels triangles</span> </button> <ul id="toc-Propietats_dels_triangles-sublist" class="vector-toc-list"> <li id="toc-Suma_dels_angles_d&#039;un_triangle" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Suma_dels_angles_d&#039;un_triangle"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.1</span> <span>Suma dels angles d'un triangle</span> </div> </a> <ul id="toc-Suma_dels_angles_d&#039;un_triangle-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Longituds_dels_costats_i_desigualtat_triangular" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Longituds_dels_costats_i_desigualtat_triangular"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.2</span> <span>Longituds dels costats i desigualtat triangular</span> </div> </a> <ul id="toc-Longituds_dels_costats_i_desigualtat_triangular-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Relacions_mètriques_en_un_triangle" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Relacions_mètriques_en_un_triangle"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.3</span> <span>Relacions mètriques en un triangle</span> </div> </a> <ul id="toc-Relacions_mètriques_en_un_triangle-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Triangles_semblants_i_isomètrics" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Triangles_semblants_i_isomètrics"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.4</span> <span>Triangles semblants i isomètrics</span> </div> </a> <ul id="toc-Triangles_semblants_i_isomètrics-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Aplicacions_dels_triangles" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Aplicacions_dels_triangles"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>Aplicacions dels triangles</span> </div> </a> <ul id="toc-Aplicacions_dels_triangles-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Políedres_de_cares_triangulars" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Políedres_de_cares_triangulars"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>Políedres de cares triangulars</span> </div> </a> <ul id="toc-Políedres_de_cares_triangulars-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Triangles_no_plans" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Triangles_no_plans"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>Triangles no plans</span> </div> </a> <ul id="toc-Triangles_no_plans-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Triangle_de_Sierpiński" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Triangle_de_Sierpiński"> <div class="vector-toc-text"> <span class="vector-toc-numb">9</span> <span>Triangle de Sierpiński</span> </div> </a> <ul id="toc-Triangle_de_Sierpiński-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Simbolisme_del_triangle" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Simbolisme_del_triangle"> <div class="vector-toc-text"> <span class="vector-toc-numb">10</span> <span>Simbolisme del triangle</span> </div> </a> <ul id="toc-Simbolisme_del_triangle-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Referències" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Referències"> <div class="vector-toc-text"> <span class="vector-toc-numb">11</span> <span>Referències</span> </div> </a> <ul id="toc-Referències-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Vegeu_també" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Vegeu_també"> <div class="vector-toc-text"> <span class="vector-toc-numb">12</span> <span>Vegeu també</span> </div> </a> <ul id="toc-Vegeu_també-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Enllaços_externs" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Enllaços_externs"> <div class="vector-toc-text"> <span class="vector-toc-numb">13</span> <span>Enllaços externs</span> </div> </a> <ul id="toc-Enllaços_externs-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contingut" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Commuta la taula de continguts." > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Commuta la taula de continguts.</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">Triangle</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Vés a un article en una altra llengua. Disponible en 162 llengües" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-162" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">162 llengües</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ab mw-list-item"><a href="https://ab.wikipedia.org/wiki/%D0%90%D1%85%D0%BA%D3%99%D0%B0%D0%BA%D1%8C" title="Ахкәакь - abkhaz" lang="ab" hreflang="ab" data-title="Ахкәакь" data-language-autonym="Аԥсшәа" data-language-local-name="abkhaz" class="interlanguage-link-target"><span>Аԥсшәа</span></a></li><li class="interlanguage-link interwiki-af mw-list-item"><a href="https://af.wikipedia.org/wiki/Driehoek" title="Driehoek - afrikaans" lang="af" hreflang="af" data-title="Driehoek" data-language-autonym="Afrikaans" data-language-local-name="afrikaans" class="interlanguage-link-target"><span>Afrikaans</span></a></li><li class="interlanguage-link interwiki-als mw-list-item"><a href="https://als.wikipedia.org/wiki/Dreieck" title="Dreieck - alemany suís" lang="gsw" hreflang="gsw" data-title="Dreieck" data-language-autonym="Alemannisch" data-language-local-name="alemany suís" class="interlanguage-link-target"><span>Alemannisch</span></a></li><li class="interlanguage-link interwiki-am mw-list-item"><a href="https://am.wikipedia.org/wiki/%E1%88%B6%E1%88%B5%E1%89%B5_%E1%88%9B%E1%8A%A5%E1%8B%98%E1%8A%95" title="ሶስት ማእዘን - amhàric" lang="am" hreflang="am" data-title="ሶስት ማእዘን" data-language-autonym="አማርኛ" data-language-local-name="amhàric" class="interlanguage-link-target"><span>አማርኛ</span></a></li><li class="interlanguage-link interwiki-an mw-list-item"><a href="https://an.wikipedia.org/wiki/Trianglo" title="Trianglo - aragonès" lang="an" hreflang="an" data-title="Trianglo" data-language-autonym="Aragonés" data-language-local-name="aragonès" class="interlanguage-link-target"><span>Aragonés</span></a></li><li class="interlanguage-link interwiki-ang mw-list-item"><a href="https://ang.wikipedia.org/wiki/%C3%9Er%C4%ABecge" title="Þrīecge - anglès antic" lang="ang" hreflang="ang" data-title="Þrīecge" data-language-autonym="Ænglisc" data-language-local-name="anglès antic" class="interlanguage-link-target"><span>Ænglisc</span></a></li><li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D9%85%D8%AB%D9%84%D8%AB" title="مثلث - àrab" lang="ar" hreflang="ar" data-title="مثلث" data-language-autonym="العربية" data-language-local-name="àrab" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-arc mw-list-item"><a href="https://arc.wikipedia.org/wiki/%DC%A1%DC%AC%DC%A0%DC%AC%DC%90" title="ܡܬܠܬܐ - arameu" lang="arc" hreflang="arc" data-title="ܡܬܠܬܐ" data-language-autonym="ܐܪܡܝܐ" data-language-local-name="arameu" class="interlanguage-link-target"><span>ܐܪܡܝܐ</span></a></li><li class="interlanguage-link interwiki-ary mw-list-item"><a href="https://ary.wikipedia.org/wiki/%D9%85%D8%AA%D9%84%D8%AA" title="متلت - Moroccan Arabic" lang="ary" hreflang="ary" data-title="متلت" data-language-autonym="الدارجة" data-language-local-name="Moroccan Arabic" class="interlanguage-link-target"><span>الدارجة</span></a></li><li class="interlanguage-link interwiki-arz mw-list-item"><a href="https://arz.wikipedia.org/wiki/%D9%85%D8%AB%D9%84%D8%AB" title="مثلث - àrab egipci" lang="arz" hreflang="arz" data-title="مثلث" data-language-autonym="مصرى" data-language-local-name="àrab egipci" class="interlanguage-link-target"><span>مصرى</span></a></li><li class="interlanguage-link interwiki-as mw-list-item"><a href="https://as.wikipedia.org/wiki/%E0%A6%A4%E0%A7%8D%E0%A7%B0%E0%A6%BF%E0%A6%AD%E0%A7%81%E0%A6%9C" title="ত্ৰিভুজ - assamès" lang="as" hreflang="as" data-title="ত্ৰিভুজ" data-language-autonym="অসমীয়া" data-language-local-name="assamès" class="interlanguage-link-target"><span>অসমীয়া</span></a></li><li class="interlanguage-link interwiki-ast mw-list-item"><a href="https://ast.wikipedia.org/wiki/Tri%C3%A1ngulu" title="Triángulu - asturià" lang="ast" hreflang="ast" data-title="Triángulu" data-language-autonym="Asturianu" data-language-local-name="asturià" class="interlanguage-link-target"><span>Asturianu</span></a></li><li class="interlanguage-link interwiki-ay mw-list-item"><a href="https://ay.wikipedia.org/wiki/Mujina" title="Mujina - aimara" lang="ay" hreflang="ay" data-title="Mujina" data-language-autonym="Aymar aru" data-language-local-name="aimara" class="interlanguage-link-target"><span>Aymar aru</span></a></li><li class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikipedia.org/wiki/%C3%9C%C3%A7bucaq" title="Üçbucaq - azerbaidjanès" lang="az" hreflang="az" data-title="Üçbucaq" data-language-autonym="Azərbaycanca" data-language-local-name="azerbaidjanès" class="interlanguage-link-target"><span>Azərbaycanca</span></a></li><li class="interlanguage-link interwiki-azb mw-list-item"><a href="https://azb.wikipedia.org/wiki/%D8%A7%D9%88%DA%86%E2%80%8C%D8%A8%D9%88%D8%AC%D8%A7%D9%82" title="اوچ‌بوجاق - South Azerbaijani" lang="azb" hreflang="azb" data-title="اوچ‌بوجاق" data-language-autonym="تۆرکجه" data-language-local-name="South Azerbaijani" class="interlanguage-link-target"><span>تۆرکجه</span></a></li><li class="interlanguage-link interwiki-ba mw-list-item"><a href="https://ba.wikipedia.org/wiki/%D3%A8%D1%81%D0%BC%D3%A9%D0%B9%D3%A9%D1%88" title="Өсмөйөш - baixkir" lang="ba" hreflang="ba" data-title="Өсмөйөш" data-language-autonym="Башҡортса" data-language-local-name="baixkir" class="interlanguage-link-target"><span>Башҡортса</span></a></li><li class="interlanguage-link interwiki-bar mw-list-item"><a href="https://bar.wikipedia.org/wiki/Dreieck" title="Dreieck - bavarès" lang="bar" hreflang="bar" data-title="Dreieck" data-language-autonym="Boarisch" data-language-local-name="bavarès" class="interlanguage-link-target"><span>Boarisch</span></a></li><li class="interlanguage-link interwiki-bat-smg mw-list-item"><a href="https://bat-smg.wikipedia.org/wiki/Tr%C4%97kompis" title="Trėkompis - Samogitian" lang="sgs" hreflang="sgs" data-title="Trėkompis" data-language-autonym="Žemaitėška" data-language-local-name="Samogitian" class="interlanguage-link-target"><span>Žemaitėška</span></a></li><li class="interlanguage-link interwiki-bcl mw-list-item"><a href="https://bcl.wikipedia.org/wiki/Trianggulo" title="Trianggulo - Central Bikol" lang="bcl" hreflang="bcl" data-title="Trianggulo" data-language-autonym="Bikol Central" data-language-local-name="Central Bikol" class="interlanguage-link-target"><span>Bikol Central</span></a></li><li class="interlanguage-link interwiki-be mw-list-item"><a href="https://be.wikipedia.org/wiki/%D0%A2%D1%80%D0%BE%D1%85%D0%B2%D1%83%D0%B3%D0%BE%D0%BB%D1%8C%D0%BD%D1%96%D0%BA" title="Трохвугольнік - belarús" lang="be" hreflang="be" data-title="Трохвугольнік" data-language-autonym="Беларуская" data-language-local-name="belarús" class="interlanguage-link-target"><span>Беларуская</span></a></li><li class="interlanguage-link interwiki-be-x-old mw-list-item"><a href="https://be-tarask.wikipedia.org/wiki/%D0%A2%D1%80%D1%8B%D0%BA%D1%83%D1%82%D0%BD%D1%96%D0%BA" title="Трыкутнік - Belarusian (Taraškievica orthography)" lang="be-tarask" hreflang="be-tarask" data-title="Трыкутнік" data-language-autonym="Беларуская (тарашкевіца)" data-language-local-name="Belarusian (Taraškievica orthography)" class="interlanguage-link-target"><span>Беларуская (тарашкевіца)</span></a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/%D0%A2%D1%80%D0%B8%D1%8A%D0%B3%D1%8A%D0%BB%D0%BD%D0%B8%D0%BA" title="Триъгълник - búlgar" lang="bg" hreflang="bg" data-title="Триъгълник" data-language-autonym="Български" data-language-local-name="búlgar" class="interlanguage-link-target"><span>Български</span></a></li><li class="interlanguage-link interwiki-bh mw-list-item"><a href="https://bh.wikipedia.org/wiki/%E0%A4%A4%E0%A5%8D%E0%A4%B0%E0%A4%BF%E0%A4%AD%E0%A5%81%E0%A4%9C" title="त्रिभुज - Bhojpuri" lang="bh" hreflang="bh" data-title="त्रिभुज" data-language-autonym="भोजपुरी" data-language-local-name="Bhojpuri" class="interlanguage-link-target"><span>भोजपुरी</span></a></li><li class="interlanguage-link interwiki-bn mw-list-item"><a href="https://bn.wikipedia.org/wiki/%E0%A6%A4%E0%A7%8D%E0%A6%B0%E0%A6%BF%E0%A6%AD%E0%A7%81%E0%A6%9C" title="ত্রিভুজ - bengalí" lang="bn" hreflang="bn" data-title="ত্রিভুজ" data-language-autonym="বাংলা" data-language-local-name="bengalí" class="interlanguage-link-target"><span>বাংলা</span></a></li><li class="interlanguage-link interwiki-bo mw-list-item"><a href="https://bo.wikipedia.org/wiki/%E0%BD%A6%E0%BD%9F%E0%BD%B4%E0%BD%A2%E0%BC%8B%E0%BD%82%E0%BD%A6%E0%BD%B4%E0%BD%98%E0%BC%8B%E0%BD%91%E0%BD%96%E0%BD%96%E0%BE%B1%E0%BD%B2%E0%BC%8D" title="སཟུར་གསུམ་དབབྱི། - tibetà" lang="bo" hreflang="bo" data-title="སཟུར་གསུམ་དབབྱི།" data-language-autonym="བོད་ཡིག" data-language-local-name="tibetà" class="interlanguage-link-target"><span>བོད་ཡིག</span></a></li><li class="interlanguage-link interwiki-br mw-list-item"><a href="https://br.wikipedia.org/wiki/Tric%27horn" title="Tric&#039;horn - bretó" lang="br" hreflang="br" data-title="Tric&#039;horn" data-language-autonym="Brezhoneg" data-language-local-name="bretó" class="interlanguage-link-target"><span>Brezhoneg</span></a></li><li class="interlanguage-link interwiki-bs mw-list-item"><a href="https://bs.wikipedia.org/wiki/Trougao" title="Trougao - bosnià" lang="bs" hreflang="bs" data-title="Trougao" data-language-autonym="Bosanski" data-language-local-name="bosnià" class="interlanguage-link-target"><span>Bosanski</span></a></li><li class="interlanguage-link interwiki-cdo mw-list-item"><a href="https://cdo.wikipedia.org/wiki/S%C4%83ng-g%C3%A1e%CC%A4k-h%C3%ACng" title="Săng-gáe̤k-hìng - Mindong" lang="cdo" hreflang="cdo" data-title="Săng-gáe̤k-hìng" data-language-autonym="閩東語 / Mìng-dĕ̤ng-ngṳ̄" data-language-local-name="Mindong" class="interlanguage-link-target"><span>閩東語 / Mìng-dĕ̤ng-ngṳ̄</span></a></li><li class="interlanguage-link interwiki-chr mw-list-item"><a href="https://chr.wikipedia.org/wiki/%E1%8F%A6%E1%8E%A2_%E1%8F%A7%E1%8F%85%E1%8F%8F%E1%8F%AF_%E1%8E%A4%E1%8F%83%E1%8F%B4%E1%8E%A9" title="ᏦᎢ ᏧᏅᏏᏯ ᎤᏃᏴᎩ - cherokee" lang="chr" hreflang="chr" data-title="ᏦᎢ ᏧᏅᏏᏯ ᎤᏃᏴᎩ" data-language-autonym="ᏣᎳᎩ" data-language-local-name="cherokee" class="interlanguage-link-target"><span>ᏣᎳᎩ</span></a></li><li class="interlanguage-link interwiki-ckb mw-list-item"><a href="https://ckb.wikipedia.org/wiki/%D8%B3%DB%8E%DA%AF%DB%86%D8%B4%DB%95" title="سێگۆشە - kurd central" lang="ckb" hreflang="ckb" data-title="سێگۆشە" data-language-autonym="کوردی" data-language-local-name="kurd central" class="interlanguage-link-target"><span>کوردی</span></a></li><li class="interlanguage-link interwiki-co mw-list-item"><a href="https://co.wikipedia.org/wiki/Triangulu" title="Triangulu - cors" lang="co" hreflang="co" data-title="Triangulu" data-language-autonym="Corsu" data-language-local-name="cors" class="interlanguage-link-target"><span>Corsu</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Troj%C3%BAheln%C3%ADk" title="Trojúhelník - txec" lang="cs" hreflang="cs" data-title="Trojúhelník" data-language-autonym="Čeština" data-language-local-name="txec" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-csb mw-list-item"><a href="https://csb.wikipedia.org/wiki/Trz%C3%ABn%C3%B3rt" title="Trzënórt - caixubi" lang="csb" hreflang="csb" data-title="Trzënórt" data-language-autonym="Kaszëbsczi" data-language-local-name="caixubi" class="interlanguage-link-target"><span>Kaszëbsczi</span></a></li><li class="interlanguage-link interwiki-cv mw-list-item"><a href="https://cv.wikipedia.org/wiki/%D0%92%D0%B8%C3%A7%D0%BA%C4%95%D1%82%D0%B5%D1%81%D0%BB%C4%95%D1%85" title="Виçкĕтеслĕх - txuvaix" lang="cv" hreflang="cv" data-title="Виçкĕтеслĕх" data-language-autonym="Чӑвашла" data-language-local-name="txuvaix" class="interlanguage-link-target"><span>Чӑвашла</span></a></li><li class="interlanguage-link interwiki-cy mw-list-item"><a href="https://cy.wikipedia.org/wiki/Triongl" title="Triongl - gal·lès" lang="cy" hreflang="cy" data-title="Triongl" data-language-autonym="Cymraeg" data-language-local-name="gal·lès" class="interlanguage-link-target"><span>Cymraeg</span></a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/Trekant" title="Trekant - danès" lang="da" hreflang="da" data-title="Trekant" data-language-autonym="Dansk" data-language-local-name="danès" class="interlanguage-link-target"><span>Dansk</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Dreieck" title="Dreieck - alemany" lang="de" hreflang="de" data-title="Dreieck" data-language-autonym="Deutsch" data-language-local-name="alemany" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-diq mw-list-item"><a href="https://diq.wikipedia.org/wiki/Hir%C3%AAk%C4%B1nari" title="Hirêkınari - Zazaki" lang="diq" hreflang="diq" data-title="Hirêkınari" data-language-autonym="Zazaki" data-language-local-name="Zazaki" class="interlanguage-link-target"><span>Zazaki</span></a></li><li class="interlanguage-link interwiki-dsb mw-list-item"><a href="https://dsb.wikipedia.org/wiki/T%C5%9Biro%C5%BEk" title="Tśirožk - baix sòrab" lang="dsb" hreflang="dsb" data-title="Tśirožk" data-language-autonym="Dolnoserbski" data-language-local-name="baix sòrab" class="interlanguage-link-target"><span>Dolnoserbski</span></a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/%CE%A4%CF%81%CE%AF%CE%B3%CF%89%CE%BD%CE%BF" title="Τρίγωνο - grec" lang="el" hreflang="el" data-title="Τρίγωνο" data-language-autonym="Ελληνικά" data-language-local-name="grec" class="interlanguage-link-target"><span>Ελληνικά</span></a></li><li class="interlanguage-link interwiki-en mw-list-item"><a href="https://en.wikipedia.org/wiki/Triangle" title="Triangle - anglès" lang="en" hreflang="en" data-title="Triangle" data-language-autonym="English" data-language-local-name="anglès" class="interlanguage-link-target"><span>English</span></a></li><li class="interlanguage-link interwiki-eo mw-list-item"><a href="https://eo.wikipedia.org/wiki/Triangulo" title="Triangulo - esperanto" lang="eo" hreflang="eo" data-title="Triangulo" data-language-autonym="Esperanto" data-language-local-name="esperanto" class="interlanguage-link-target"><span>Esperanto</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Tri%C3%A1ngulo" title="Triángulo - espanyol" lang="es" hreflang="es" data-title="Triángulo" data-language-autonym="Español" data-language-local-name="espanyol" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/Kolmnurk" title="Kolmnurk - estonià" lang="et" hreflang="et" data-title="Kolmnurk" data-language-autonym="Eesti" data-language-local-name="estonià" class="interlanguage-link-target"><span>Eesti</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/Triangelu" title="Triangelu - basc" lang="eu" hreflang="eu" data-title="Triangelu" data-language-autonym="Euskara" data-language-local-name="basc" class="interlanguage-link-target"><span>Euskara</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D9%85%D8%AB%D9%84%D8%AB" title="مثلث - persa" lang="fa" hreflang="fa" data-title="مثلث" data-language-autonym="فارسی" data-language-local-name="persa" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/Kolmio" title="Kolmio - finès" lang="fi" hreflang="fi" data-title="Kolmio" data-language-autonym="Suomi" data-language-local-name="finès" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-fiu-vro mw-list-item"><a href="https://fiu-vro.wikipedia.org/wiki/Kolmnukk" title="Kolmnukk - Võro" lang="vro" hreflang="vro" data-title="Kolmnukk" data-language-autonym="Võro" data-language-local-name="Võro" class="interlanguage-link-target"><span>Võro</span></a></li><li class="interlanguage-link interwiki-fj mw-list-item"><a href="https://fj.wikipedia.org/wiki/Tututolu" title="Tututolu - fijià" lang="fj" hreflang="fj" data-title="Tututolu" data-language-autonym="Na Vosa Vakaviti" data-language-local-name="fijià" class="interlanguage-link-target"><span>Na Vosa Vakaviti</span></a></li><li class="interlanguage-link interwiki-fo mw-list-item"><a href="https://fo.wikipedia.org/wiki/Tr%C3%ADkantur" title="Tríkantur - feroès" lang="fo" hreflang="fo" data-title="Tríkantur" data-language-autonym="Føroyskt" data-language-local-name="feroès" class="interlanguage-link-target"><span>Føroyskt</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Triangle" title="Triangle - francès" lang="fr" hreflang="fr" data-title="Triangle" data-language-autonym="Français" data-language-local-name="francès" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-frr mw-list-item"><a href="https://frr.wikipedia.org/wiki/Triihuk" title="Triihuk - frisó septentrional" lang="frr" hreflang="frr" data-title="Triihuk" data-language-autonym="Nordfriisk" data-language-local-name="frisó septentrional" class="interlanguage-link-target"><span>Nordfriisk</span></a></li><li class="interlanguage-link interwiki-ga mw-list-item"><a href="https://ga.wikipedia.org/wiki/Triant%C3%A1n_(c%C3%A9imseata)" title="Triantán (céimseata) - irlandès" lang="ga" hreflang="ga" data-title="Triantán (céimseata)" data-language-autonym="Gaeilge" data-language-local-name="irlandès" class="interlanguage-link-target"><span>Gaeilge</span></a></li><li class="interlanguage-link interwiki-gan mw-list-item"><a href="https://gan.wikipedia.org/wiki/%E4%B8%89%E8%A7%92%E5%BD%A2" title="三角形 - xinès gan" lang="gan" hreflang="gan" data-title="三角形" data-language-autonym="贛語" data-language-local-name="xinès gan" class="interlanguage-link-target"><span>贛語</span></a></li><li class="interlanguage-link interwiki-gcr mw-list-item"><a href="https://gcr.wikipedia.org/wiki/Triyang" title="Triyang - Guianan Creole" lang="gcr" hreflang="gcr" data-title="Triyang" data-language-autonym="Kriyòl gwiyannen" data-language-local-name="Guianan Creole" class="interlanguage-link-target"><span>Kriyòl gwiyannen</span></a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/Tri%C3%A1ngulo" title="Triángulo - gallec" lang="gl" hreflang="gl" data-title="Triángulo" data-language-autonym="Galego" data-language-local-name="gallec" class="interlanguage-link-target"><span>Galego</span></a></li><li class="interlanguage-link interwiki-gu mw-list-item"><a href="https://gu.wikipedia.org/wiki/%E0%AA%A4%E0%AB%8D%E0%AA%B0%E0%AA%BF%E0%AA%95%E0%AB%8B%E0%AA%A3" title="ત્રિકોણ - gujarati" lang="gu" hreflang="gu" data-title="ત્રિકોણ" data-language-autonym="ગુજરાતી" data-language-local-name="gujarati" class="interlanguage-link-target"><span>ગુજરાતી</span></a></li><li class="interlanguage-link interwiki-guc mw-list-item"><a href="https://guc.wikipedia.org/wiki/Ap%C3%BCn%C3%BCinsheke%27einr%C3%BC" title="Apünüinsheke&#039;einrü - wayú" lang="guc" hreflang="guc" data-title="Apünüinsheke&#039;einrü" data-language-autonym="Wayuunaiki" data-language-local-name="wayú" class="interlanguage-link-target"><span>Wayuunaiki</span></a></li><li class="interlanguage-link interwiki-gv mw-list-item"><a href="https://gv.wikipedia.org/wiki/Troorane" title="Troorane - manx" lang="gv" hreflang="gv" data-title="Troorane" data-language-autonym="Gaelg" data-language-local-name="manx" class="interlanguage-link-target"><span>Gaelg</span></a></li><li class="interlanguage-link interwiki-hak mw-list-item"><a href="https://hak.wikipedia.org/wiki/S%C3%A2m-kok-h%C3%ACn" title="Sâm-kok-hìn - xinès hakka" lang="hak" hreflang="hak" data-title="Sâm-kok-hìn" data-language-autonym="客家語 / Hak-kâ-ngî" data-language-local-name="xinès hakka" class="interlanguage-link-target"><span>客家語 / Hak-kâ-ngî</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%9E%D7%A9%D7%95%D7%9C%D7%A9" title="משולש - hebreu" lang="he" hreflang="he" data-title="משולש" data-language-autonym="עברית" data-language-local-name="hebreu" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%A4%E0%A5%8D%E0%A4%B0%E0%A4%BF%E0%A4%AD%E0%A5%81%E0%A4%9C" title="त्रिभुज - hindi" lang="hi" hreflang="hi" data-title="त्रिभुज" data-language-autonym="हिन्दी" data-language-local-name="hindi" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-hr mw-list-item"><a href="https://hr.wikipedia.org/wiki/Trokut" title="Trokut - croat" lang="hr" hreflang="hr" data-title="Trokut" data-language-autonym="Hrvatski" data-language-local-name="croat" class="interlanguage-link-target"><span>Hrvatski</span></a></li><li class="interlanguage-link interwiki-hsb mw-list-item"><a href="https://hsb.wikipedia.org/wiki/T%C5%99ir%C3%B3%C5%BEk" title="Třiróžk - alt sòrab" lang="hsb" hreflang="hsb" data-title="Třiróžk" data-language-autonym="Hornjoserbsce" data-language-local-name="alt sòrab" class="interlanguage-link-target"><span>Hornjoserbsce</span></a></li><li class="interlanguage-link interwiki-ht mw-list-item"><a href="https://ht.wikipedia.org/wiki/Triyang" title="Triyang - crioll d’Haití" lang="ht" hreflang="ht" data-title="Triyang" data-language-autonym="Kreyòl ayisyen" data-language-local-name="crioll d’Haití" class="interlanguage-link-target"><span>Kreyòl ayisyen</span></a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/H%C3%A1romsz%C3%B6g" title="Háromszög - hongarès" lang="hu" hreflang="hu" data-title="Háromszög" data-language-autonym="Magyar" data-language-local-name="hongarès" class="interlanguage-link-target"><span>Magyar</span></a></li><li class="interlanguage-link interwiki-hy mw-list-item"><a href="https://hy.wikipedia.org/wiki/%D4%B5%D5%BC%D5%A1%D5%B6%D5%AF%D5%B5%D5%B8%D6%82%D5%B6" title="Եռանկյուն - armeni" lang="hy" hreflang="hy" data-title="Եռանկյուն" data-language-autonym="Հայերեն" data-language-local-name="armeni" class="interlanguage-link-target"><span>Հայերեն</span></a></li><li class="interlanguage-link interwiki-ia mw-list-item"><a href="https://ia.wikipedia.org/wiki/Triangulo" title="Triangulo - interlingua" lang="ia" hreflang="ia" data-title="Triangulo" data-language-autonym="Interlingua" data-language-local-name="interlingua" class="interlanguage-link-target"><span>Interlingua</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Segitiga" title="Segitiga - indonesi" lang="id" hreflang="id" data-title="Segitiga" data-language-autonym="Bahasa Indonesia" data-language-local-name="indonesi" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-io mw-list-item"><a href="https://io.wikipedia.org/wiki/Triangulo" title="Triangulo - ido" lang="io" hreflang="io" data-title="Triangulo" data-language-autonym="Ido" data-language-local-name="ido" class="interlanguage-link-target"><span>Ido</span></a></li><li class="interlanguage-link interwiki-is mw-list-item"><a href="https://is.wikipedia.org/wiki/%C3%9Er%C3%ADhyrningur" title="Þríhyrningur - islandès" lang="is" hreflang="is" data-title="Þríhyrningur" data-language-autonym="Íslenska" data-language-local-name="islandès" class="interlanguage-link-target"><span>Íslenska</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Triangolo" title="Triangolo - italià" lang="it" hreflang="it" data-title="Triangolo" data-language-autonym="Italiano" data-language-local-name="italià" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E4%B8%89%E8%A7%92%E5%BD%A2" title="三角形 - japonès" lang="ja" hreflang="ja" data-title="三角形" data-language-autonym="日本語" data-language-local-name="japonès" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-jam mw-list-item"><a href="https://jam.wikipedia.org/wiki/Chrayanggl" title="Chrayanggl - crioll anglès de Jamaica" lang="jam" hreflang="jam" data-title="Chrayanggl" data-language-autonym="Patois" data-language-local-name="crioll anglès de Jamaica" class="interlanguage-link-target"><span>Patois</span></a></li><li class="interlanguage-link interwiki-jv mw-list-item"><a href="https://jv.wikipedia.org/wiki/Pasagi_telu" title="Pasagi telu - javanès" lang="jv" hreflang="jv" data-title="Pasagi telu" data-language-autonym="Jawa" data-language-local-name="javanès" class="interlanguage-link-target"><span>Jawa</span></a></li><li class="interlanguage-link interwiki-ka badge-Q17437796 badge-featuredarticle mw-list-item" title="article de qualitat"><a href="https://ka.wikipedia.org/wiki/%E1%83%A1%E1%83%90%E1%83%9B%E1%83%99%E1%83%A3%E1%83%97%E1%83%AE%E1%83%94%E1%83%93%E1%83%98" title="სამკუთხედი - georgià" lang="ka" hreflang="ka" data-title="სამკუთხედი" data-language-autonym="ქართული" data-language-local-name="georgià" class="interlanguage-link-target"><span>ქართული</span></a></li><li class="interlanguage-link interwiki-kaa mw-list-item"><a href="https://kaa.wikipedia.org/wiki/%C3%9Ashm%C3%BAyeshlik" title="Úshmúyeshlik - karakalpak" lang="kaa" hreflang="kaa" data-title="Úshmúyeshlik" data-language-autonym="Qaraqalpaqsha" data-language-local-name="karakalpak" class="interlanguage-link-target"><span>Qaraqalpaqsha</span></a></li><li class="interlanguage-link interwiki-kbd mw-list-item"><a href="https://kbd.wikipedia.org/wiki/%D0%A9%D0%B8%D0%BC%D1%8D" title="Щимэ - kabardí" lang="kbd" hreflang="kbd" data-title="Щимэ" data-language-autonym="Адыгэбзэ" data-language-local-name="kabardí" class="interlanguage-link-target"><span>Адыгэбзэ</span></a></li><li class="interlanguage-link interwiki-kk mw-list-item"><a href="https://kk.wikipedia.org/wiki/%D2%AE%D1%88%D0%B1%D2%B1%D1%80%D1%8B%D1%88" title="Үшбұрыш - kazakh" lang="kk" hreflang="kk" data-title="Үшбұрыш" data-language-autonym="Қазақша" data-language-local-name="kazakh" class="interlanguage-link-target"><span>Қазақша</span></a></li><li class="interlanguage-link interwiki-km badge-Q17437796 badge-featuredarticle mw-list-item" title="article de qualitat"><a href="https://km.wikipedia.org/wiki/%E1%9E%8F%E1%9F%92%E1%9E%9A%E1%9E%B8%E1%9E%80%E1%9F%84%E1%9E%8E" title="ត្រីកោណ - khmer" lang="km" hreflang="km" data-title="ត្រីកោណ" data-language-autonym="ភាសាខ្មែរ" data-language-local-name="khmer" class="interlanguage-link-target"><span>ភាសាខ្មែរ</span></a></li><li class="interlanguage-link interwiki-kn mw-list-item"><a href="https://kn.wikipedia.org/wiki/%E0%B2%A4%E0%B3%8D%E0%B2%B0%E0%B2%BF%E0%B2%95%E0%B3%8B%E0%B2%A8" title="ತ್ರಿಕೋನ - kannada" lang="kn" hreflang="kn" data-title="ತ್ರಿಕೋನ" data-language-autonym="ಕನ್ನಡ" data-language-local-name="kannada" class="interlanguage-link-target"><span>ಕನ್ನಡ</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EC%82%BC%EA%B0%81%ED%98%95" title="삼각형 - coreà" lang="ko" hreflang="ko" data-title="삼각형" data-language-autonym="한국어" data-language-local-name="coreà" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-ku mw-list-item"><a href="https://ku.wikipedia.org/wiki/S%C3%AAgo%C5%9Fe" title="Sêgoşe - kurd" lang="ku" hreflang="ku" data-title="Sêgoşe" data-language-autonym="Kurdî" data-language-local-name="kurd" class="interlanguage-link-target"><span>Kurdî</span></a></li><li class="interlanguage-link interwiki-kw mw-list-item"><a href="https://kw.wikipedia.org/wiki/Trihorn" title="Trihorn - còrnic" lang="kw" hreflang="kw" data-title="Trihorn" data-language-autonym="Kernowek" data-language-local-name="còrnic" class="interlanguage-link-target"><span>Kernowek</span></a></li><li class="interlanguage-link interwiki-ky mw-list-item"><a href="https://ky.wikipedia.org/wiki/%D2%AE%D1%87_%D0%B1%D1%83%D1%80%D1%87%D1%82%D1%83%D0%BA" title="Үч бурчтук - kirguís" lang="ky" hreflang="ky" data-title="Үч бурчтук" data-language-autonym="Кыргызча" data-language-local-name="kirguís" class="interlanguage-link-target"><span>Кыргызча</span></a></li><li class="interlanguage-link interwiki-la mw-list-item"><a href="https://la.wikipedia.org/wiki/Triangulum" title="Triangulum - llatí" lang="la" hreflang="la" data-title="Triangulum" data-language-autonym="Latina" data-language-local-name="llatí" class="interlanguage-link-target"><span>Latina</span></a></li><li class="interlanguage-link interwiki-lfn mw-list-item"><a href="https://lfn.wikipedia.org/wiki/Triangulo" title="Triangulo - Lingua Franca Nova" lang="lfn" hreflang="lfn" data-title="Triangulo" data-language-autonym="Lingua Franca Nova" data-language-local-name="Lingua Franca Nova" class="interlanguage-link-target"><span>Lingua Franca Nova</span></a></li><li class="interlanguage-link interwiki-li mw-list-item"><a href="https://li.wikipedia.org/wiki/Driehook" title="Driehook - limburguès" lang="li" hreflang="li" data-title="Driehook" data-language-autonym="Limburgs" data-language-local-name="limburguès" class="interlanguage-link-target"><span>Limburgs</span></a></li><li class="interlanguage-link interwiki-lij mw-list-item"><a href="https://lij.wikipedia.org/wiki/Triangolo" title="Triangolo - lígur" lang="lij" hreflang="lij" data-title="Triangolo" data-language-autonym="Ligure" data-language-local-name="lígur" class="interlanguage-link-target"><span>Ligure</span></a></li><li class="interlanguage-link interwiki-lmo mw-list-item"><a href="https://lmo.wikipedia.org/wiki/Tri%C3%A0ngol" title="Triàngol - llombard" lang="lmo" hreflang="lmo" data-title="Triàngol" data-language-autonym="Lombard" data-language-local-name="llombard" class="interlanguage-link-target"><span>Lombard</span></a></li><li class="interlanguage-link interwiki-ln mw-list-item"><a href="https://ln.wikipedia.org/wiki/Mpanzi-mis%C3%A1to" title="Mpanzi-misáto - lingala" lang="ln" hreflang="ln" data-title="Mpanzi-misáto" data-language-autonym="Lingála" data-language-local-name="lingala" class="interlanguage-link-target"><span>Lingála</span></a></li><li class="interlanguage-link interwiki-lo mw-list-item"><a href="https://lo.wikipedia.org/wiki/%E0%BA%AE%E0%BA%B9%E0%BA%9A%E0%BA%AA%E0%BA%B2%E0%BA%A1%E0%BB%81%E0%BA%88" title="ຮູບສາມແຈ - laosià" lang="lo" hreflang="lo" data-title="ຮູບສາມແຈ" data-language-autonym="ລາວ" data-language-local-name="laosià" class="interlanguage-link-target"><span>ລາວ</span></a></li><li class="interlanguage-link interwiki-lt mw-list-item"><a href="https://lt.wikipedia.org/wiki/Trikampis" title="Trikampis - lituà" lang="lt" hreflang="lt" data-title="Trikampis" data-language-autonym="Lietuvių" data-language-local-name="lituà" class="interlanguage-link-target"><span>Lietuvių</span></a></li><li class="interlanguage-link interwiki-lv mw-list-item"><a href="https://lv.wikipedia.org/wiki/Trijst%C5%ABris" title="Trijstūris - letó" lang="lv" hreflang="lv" data-title="Trijstūris" data-language-autonym="Latviešu" data-language-local-name="letó" class="interlanguage-link-target"><span>Latviešu</span></a></li><li class="interlanguage-link interwiki-mg mw-list-item"><a href="https://mg.wikipedia.org/wiki/Telolafy" title="Telolafy - malgaix" lang="mg" hreflang="mg" data-title="Telolafy" data-language-autonym="Malagasy" data-language-local-name="malgaix" class="interlanguage-link-target"><span>Malagasy</span></a></li><li class="interlanguage-link interwiki-mhr mw-list-item"><a href="https://mhr.wikipedia.org/wiki/%D0%9A%D1%83%D0%BC%D0%BB%D1%83%D0%BA" title="Кумлук - Eastern Mari" lang="mhr" hreflang="mhr" data-title="Кумлук" data-language-autonym="Олык марий" data-language-local-name="Eastern Mari" class="interlanguage-link-target"><span>Олык марий</span></a></li><li class="interlanguage-link interwiki-min mw-list-item"><a href="https://min.wikipedia.org/wiki/Sagitigo" title="Sagitigo - minangkabau" lang="min" hreflang="min" data-title="Sagitigo" data-language-autonym="Minangkabau" data-language-local-name="minangkabau" class="interlanguage-link-target"><span>Minangkabau</span></a></li><li class="interlanguage-link interwiki-mk mw-list-item"><a href="https://mk.wikipedia.org/wiki/%D0%A2%D1%80%D0%B8%D0%B0%D0%B3%D0%BE%D0%BB%D0%BD%D0%B8%D0%BA" title="Триаголник - macedoni" lang="mk" hreflang="mk" data-title="Триаголник" data-language-autonym="Македонски" data-language-local-name="macedoni" class="interlanguage-link-target"><span>Македонски</span></a></li><li class="interlanguage-link interwiki-ml mw-list-item"><a href="https://ml.wikipedia.org/wiki/%E0%B4%A4%E0%B5%8D%E0%B4%B0%E0%B4%BF%E0%B4%95%E0%B5%8B%E0%B4%A3%E0%B4%82" title="ത്രികോണം - malaiàlam" lang="ml" hreflang="ml" data-title="ത്രികോണം" data-language-autonym="മലയാളം" data-language-local-name="malaiàlam" class="interlanguage-link-target"><span>മലയാളം</span></a></li><li class="interlanguage-link interwiki-mn badge-Q17437796 badge-featuredarticle mw-list-item" title="article de qualitat"><a href="https://mn.wikipedia.org/wiki/%D0%93%D1%83%D1%80%D0%B2%D0%B0%D0%BB%D0%B6%D0%B8%D0%BD" title="Гурвалжин - mongol" lang="mn" hreflang="mn" data-title="Гурвалжин" data-language-autonym="Монгол" data-language-local-name="mongol" class="interlanguage-link-target"><span>Монгол</span></a></li><li class="interlanguage-link interwiki-mr mw-list-item"><a href="https://mr.wikipedia.org/wiki/%E0%A4%A4%E0%A5%8D%E0%A4%B0%E0%A4%BF%E0%A4%95%E0%A5%8B%E0%A4%A3" title="त्रिकोण - marathi" lang="mr" hreflang="mr" data-title="त्रिकोण" data-language-autonym="मराठी" data-language-local-name="marathi" class="interlanguage-link-target"><span>मराठी</span></a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Segi_tiga" title="Segi tiga - malai" lang="ms" hreflang="ms" data-title="Segi tiga" data-language-autonym="Bahasa Melayu" data-language-local-name="malai" class="interlanguage-link-target"><span>Bahasa Melayu</span></a></li><li class="interlanguage-link interwiki-mt mw-list-item"><a href="https://mt.wikipedia.org/wiki/Trijangolu" title="Trijangolu - maltès" lang="mt" hreflang="mt" data-title="Trijangolu" data-language-autonym="Malti" data-language-local-name="maltès" class="interlanguage-link-target"><span>Malti</span></a></li><li class="interlanguage-link interwiki-my mw-list-item"><a href="https://my.wikipedia.org/wiki/%E1%80%90%E1%80%BC%E1%80%AD%E1%80%82%E1%80%B6" title="တြိဂံ - birmà" lang="my" hreflang="my" data-title="တြိဂံ" data-language-autonym="မြန်မာဘာသာ" data-language-local-name="birmà" class="interlanguage-link-target"><span>မြန်မာဘာသာ</span></a></li><li class="interlanguage-link interwiki-ne mw-list-item"><a href="https://ne.wikipedia.org/wiki/%E0%A4%A4%E0%A5%8D%E0%A4%B0%E0%A4%BF%E0%A4%AD%E0%A5%81%E0%A4%9C" title="त्रिभुज - nepalès" lang="ne" hreflang="ne" data-title="त्रिभुज" data-language-autonym="नेपाली" data-language-local-name="nepalès" class="interlanguage-link-target"><span>नेपाली</span></a></li><li class="interlanguage-link interwiki-new mw-list-item"><a href="https://new.wikipedia.org/wiki/%E0%A4%B8%E0%A5%8D%E0%A4%B5%E0%A4%95%E0%A5%81%E0%A4%82" title="स्वकुं - newari" lang="new" hreflang="new" data-title="स्वकुं" data-language-autonym="नेपाल भाषा" data-language-local-name="newari" class="interlanguage-link-target"><span>नेपाल भाषा</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Driehoek_(meetkunde)" title="Driehoek (meetkunde) - neerlandès" lang="nl" hreflang="nl" data-title="Driehoek (meetkunde)" data-language-autonym="Nederlands" data-language-local-name="neerlandès" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/Trekant" title="Trekant - noruec nynorsk" lang="nn" hreflang="nn" data-title="Trekant" data-language-autonym="Norsk nynorsk" data-language-local-name="noruec nynorsk" class="interlanguage-link-target"><span>Norsk nynorsk</span></a></li><li class="interlanguage-link interwiki-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Trekant" title="Trekant - noruec bokmål" lang="nb" hreflang="nb" data-title="Trekant" data-language-autonym="Norsk bokmål" data-language-local-name="noruec bokmål" class="interlanguage-link-target"><span>Norsk bokmål</span></a></li><li class="interlanguage-link interwiki-nrm mw-list-item"><a href="https://nrm.wikipedia.org/wiki/Trian" title="Trian - Norman" lang="nrf" hreflang="nrf" data-title="Trian" data-language-autonym="Nouormand" data-language-local-name="Norman" class="interlanguage-link-target"><span>Nouormand</span></a></li><li class="interlanguage-link interwiki-oc mw-list-item"><a href="https://oc.wikipedia.org/wiki/Triangle" title="Triangle - occità" lang="oc" hreflang="oc" data-title="Triangle" data-language-autonym="Occitan" data-language-local-name="occità" class="interlanguage-link-target"><span>Occitan</span></a></li><li class="interlanguage-link interwiki-or mw-list-item"><a href="https://or.wikipedia.org/wiki/%E0%AC%A4%E0%AD%8D%E0%AC%B0%E0%AC%BF%E0%AC%AD%E0%AD%81%E0%AC%9C" title="ତ୍ରିଭୁଜ - oriya" lang="or" hreflang="or" data-title="ତ୍ରିଭୁଜ" data-language-autonym="ଓଡ଼ିଆ" data-language-local-name="oriya" class="interlanguage-link-target"><span>ଓଡ଼ିଆ</span></a></li><li class="interlanguage-link interwiki-pa mw-list-item"><a href="https://pa.wikipedia.org/wiki/%E0%A8%A4%E0%A8%BF%E0%A8%95%E0%A9%8B%E0%A8%A8" title="ਤਿਕੋਨ - panjabi" lang="pa" hreflang="pa" data-title="ਤਿਕੋਨ" data-language-autonym="ਪੰਜਾਬੀ" data-language-local-name="panjabi" class="interlanguage-link-target"><span>ਪੰਜਾਬੀ</span></a></li><li class="interlanguage-link interwiki-pfl mw-list-item"><a href="https://pfl.wikipedia.org/wiki/Dreieck" title="Dreieck - alemany palatí" lang="pfl" hreflang="pfl" data-title="Dreieck" data-language-autonym="Pälzisch" data-language-local-name="alemany palatí" class="interlanguage-link-target"><span>Pälzisch</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Tr%C3%B3jk%C4%85t" title="Trójkąt - polonès" lang="pl" hreflang="pl" data-title="Trójkąt" data-language-autonym="Polski" data-language-local-name="polonès" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pnb mw-list-item"><a href="https://pnb.wikipedia.org/wiki/%D8%AA%DA%A9%D9%88%D9%86" title="تکون - Western Punjabi" lang="pnb" hreflang="pnb" data-title="تکون" data-language-autonym="پنجابی" data-language-local-name="Western Punjabi" class="interlanguage-link-target"><span>پنجابی</span></a></li><li class="interlanguage-link interwiki-ps mw-list-item"><a href="https://ps.wikipedia.org/wiki/%D8%AF%D8%B1%DB%90%DA%85%D9%86%DA%89%DB%8C" title="درېڅنډی - paixtu" lang="ps" hreflang="ps" data-title="درېڅنډی" data-language-autonym="پښتو" data-language-local-name="paixtu" class="interlanguage-link-target"><span>پښتو</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Tri%C3%A2ngulo" title="Triângulo - portuguès" lang="pt" hreflang="pt" data-title="Triângulo" data-language-autonym="Português" data-language-local-name="portuguès" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-qu mw-list-item"><a href="https://qu.wikipedia.org/wiki/Kimsak%27uchu" title="Kimsak&#039;uchu - quítxua" lang="qu" hreflang="qu" data-title="Kimsak&#039;uchu" data-language-autonym="Runa Simi" data-language-local-name="quítxua" class="interlanguage-link-target"><span>Runa Simi</span></a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/Triunghi" title="Triunghi - romanès" lang="ro" hreflang="ro" data-title="Triunghi" data-language-autonym="Română" data-language-local-name="romanès" class="interlanguage-link-target"><span>Română</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%A2%D1%80%D0%B5%D1%83%D0%B3%D0%BE%D0%BB%D1%8C%D0%BD%D0%B8%D0%BA" title="Треугольник - rus" lang="ru" hreflang="ru" data-title="Треугольник" data-language-autonym="Русский" data-language-local-name="rus" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-rue mw-list-item"><a href="https://rue.wikipedia.org/wiki/%D0%A2%D1%80%D0%B8%D1%83%D0%B3%D0%BE%D0%BB%D0%BD%D0%B8%D0%BA" title="Триуголник - Rusyn" lang="rue" hreflang="rue" data-title="Триуголник" data-language-autonym="Русиньскый" data-language-local-name="Rusyn" class="interlanguage-link-target"><span>Русиньскый</span></a></li><li class="interlanguage-link interwiki-scn mw-list-item"><a href="https://scn.wikipedia.org/wiki/Tri%C3%A0nculu" title="Triànculu - sicilià" lang="scn" hreflang="scn" data-title="Triànculu" data-language-autonym="Sicilianu" data-language-local-name="sicilià" class="interlanguage-link-target"><span>Sicilianu</span></a></li><li class="interlanguage-link interwiki-sco mw-list-item"><a href="https://sco.wikipedia.org/wiki/Triangle" title="Triangle - escocès" lang="sco" hreflang="sco" data-title="Triangle" data-language-autonym="Scots" data-language-local-name="escocès" class="interlanguage-link-target"><span>Scots</span></a></li><li class="interlanguage-link interwiki-sd mw-list-item"><a href="https://sd.wikipedia.org/wiki/%D9%BD%DA%AA%D9%86%DA%8A%D9%88" title="ٽڪنڊو - sindi" lang="sd" hreflang="sd" data-title="ٽڪنڊو" data-language-autonym="سنڌي" data-language-local-name="sindi" class="interlanguage-link-target"><span>سنڌي</span></a></li><li class="interlanguage-link interwiki-se mw-list-item"><a href="https://se.wikipedia.org/wiki/Golmma%C4%8Diegat" title="Golmmačiegat - sami septentrional" lang="se" hreflang="se" data-title="Golmmačiegat" data-language-autonym="Davvisámegiella" data-language-local-name="sami septentrional" class="interlanguage-link-target"><span>Davvisámegiella</span></a></li><li class="interlanguage-link interwiki-sh mw-list-item"><a href="https://sh.wikipedia.org/wiki/Trokut" title="Trokut - serbocroat" lang="sh" hreflang="sh" data-title="Trokut" data-language-autonym="Srpskohrvatski / српскохрватски" data-language-local-name="serbocroat" class="interlanguage-link-target"><span>Srpskohrvatski / српскохрватски</span></a></li><li class="interlanguage-link interwiki-si mw-list-item"><a href="https://si.wikipedia.org/wiki/%E0%B6%AD%E0%B7%8A%E2%80%8D%E0%B6%BB%E0%B7%92%E0%B6%9A%E0%B7%9D%E0%B6%AB" title="ත්‍රිකෝණ - singalès" lang="si" hreflang="si" data-title="ත්‍රිකෝණ" data-language-autonym="සිංහල" data-language-local-name="singalès" class="interlanguage-link-target"><span>සිංහල</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Triangle" title="Triangle - Simple English" lang="en-simple" hreflang="en-simple" data-title="Triangle" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-sk mw-list-item"><a href="https://sk.wikipedia.org/wiki/Trojuholn%C3%ADk" title="Trojuholník - eslovac" lang="sk" hreflang="sk" data-title="Trojuholník" data-language-autonym="Slovenčina" data-language-local-name="eslovac" class="interlanguage-link-target"><span>Slovenčina</span></a></li><li class="interlanguage-link interwiki-sl mw-list-item"><a href="https://sl.wikipedia.org/wiki/Trikotnik" title="Trikotnik - eslovè" lang="sl" hreflang="sl" data-title="Trikotnik" data-language-autonym="Slovenščina" data-language-local-name="eslovè" class="interlanguage-link-target"><span>Slovenščina</span></a></li><li class="interlanguage-link interwiki-smn mw-list-item"><a href="https://smn.wikipedia.org/wiki/Kulm%C3%A2h%C3%A2%C5%A1" title="Kulmâhâš - sami d’Inari" lang="smn" hreflang="smn" data-title="Kulmâhâš" data-language-autonym="Anarâškielâ" data-language-local-name="sami d’Inari" class="interlanguage-link-target"><span>Anarâškielâ</span></a></li><li class="interlanguage-link interwiki-sn mw-list-item"><a href="https://sn.wikipedia.org/wiki/Gonyonhatu" title="Gonyonhatu - shona" lang="sn" hreflang="sn" data-title="Gonyonhatu" data-language-autonym="ChiShona" data-language-local-name="shona" class="interlanguage-link-target"><span>ChiShona</span></a></li><li class="interlanguage-link interwiki-so mw-list-item"><a href="https://so.wikipedia.org/wiki/Saddexagal" title="Saddexagal - somali" lang="so" hreflang="so" data-title="Saddexagal" data-language-autonym="Soomaaliga" data-language-local-name="somali" class="interlanguage-link-target"><span>Soomaaliga</span></a></li><li class="interlanguage-link interwiki-sq mw-list-item"><a href="https://sq.wikipedia.org/wiki/Trek%C3%ABnd%C3%ABshi" title="Trekëndëshi - albanès" lang="sq" hreflang="sq" data-title="Trekëndëshi" data-language-autonym="Shqip" data-language-local-name="albanès" class="interlanguage-link-target"><span>Shqip</span></a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/%D0%A2%D1%80%D0%BE%D1%83%D0%B3%D0%B0%D0%BE" title="Троугао - serbi" lang="sr" hreflang="sr" data-title="Троугао" data-language-autonym="Српски / srpski" data-language-local-name="serbi" class="interlanguage-link-target"><span>Српски / srpski</span></a></li><li class="interlanguage-link interwiki-su mw-list-item"><a href="https://su.wikipedia.org/wiki/Juru_tilu" title="Juru tilu - sondanès" lang="su" hreflang="su" data-title="Juru tilu" data-language-autonym="Sunda" data-language-local-name="sondanès" class="interlanguage-link-target"><span>Sunda</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Triangel" title="Triangel - suec" lang="sv" hreflang="sv" data-title="Triangel" data-language-autonym="Svenska" data-language-local-name="suec" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-sw mw-list-item"><a href="https://sw.wikipedia.org/wiki/Pembetatu" title="Pembetatu - suahili" lang="sw" hreflang="sw" data-title="Pembetatu" data-language-autonym="Kiswahili" data-language-local-name="suahili" class="interlanguage-link-target"><span>Kiswahili</span></a></li><li class="interlanguage-link interwiki-szl mw-list-item"><a href="https://szl.wikipedia.org/wiki/Trziek" title="Trziek - silesià" lang="szl" hreflang="szl" data-title="Trziek" data-language-autonym="Ślůnski" data-language-local-name="silesià" class="interlanguage-link-target"><span>Ślůnski</span></a></li><li class="interlanguage-link interwiki-ta mw-list-item"><a href="https://ta.wikipedia.org/wiki/%E0%AE%AE%E0%AF%81%E0%AE%95%E0%AF%8D%E0%AE%95%E0%AF%8B%E0%AE%A3%E0%AE%AE%E0%AF%8D" title="முக்கோணம் - tàmil" lang="ta" hreflang="ta" data-title="முக்கோணம்" data-language-autonym="தமிழ்" data-language-local-name="tàmil" class="interlanguage-link-target"><span>தமிழ்</span></a></li><li class="interlanguage-link interwiki-te mw-list-item"><a href="https://te.wikipedia.org/wiki/%E0%B0%A4%E0%B1%8D%E0%B0%B0%E0%B0%BF%E0%B0%AD%E0%B1%81%E0%B0%9C%E0%B0%82" title="త్రిభుజం - telugu" lang="te" hreflang="te" data-title="త్రిభుజం" data-language-autonym="తెలుగు" data-language-local-name="telugu" class="interlanguage-link-target"><span>తెలుగు</span></a></li><li class="interlanguage-link interwiki-tg mw-list-item"><a href="https://tg.wikipedia.org/wiki/%D0%A1%D0%B5%D0%BA%D1%83%D0%BD%D2%B7%D0%B0" title="Секунҷа - tadjik" lang="tg" hreflang="tg" data-title="Секунҷа" data-language-autonym="Тоҷикӣ" data-language-local-name="tadjik" class="interlanguage-link-target"><span>Тоҷикӣ</span></a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikipedia.org/wiki/%E0%B8%A3%E0%B8%B9%E0%B8%9B%E0%B8%AA%E0%B8%B2%E0%B8%A1%E0%B9%80%E0%B8%AB%E0%B8%A5%E0%B8%B5%E0%B9%88%E0%B8%A2%E0%B8%A1" title="รูปสามเหลี่ยม - tai" lang="th" hreflang="th" data-title="รูปสามเหลี่ยม" data-language-autonym="ไทย" data-language-local-name="tai" class="interlanguage-link-target"><span>ไทย</span></a></li><li class="interlanguage-link interwiki-tl mw-list-item"><a href="https://tl.wikipedia.org/wiki/Tatsulok" title="Tatsulok - tagal" lang="tl" hreflang="tl" data-title="Tatsulok" data-language-autonym="Tagalog" data-language-local-name="tagal" class="interlanguage-link-target"><span>Tagalog</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/%C3%9C%C3%A7gen" title="Üçgen - turc" lang="tr" hreflang="tr" data-title="Üçgen" data-language-autonym="Türkçe" data-language-local-name="turc" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-tt mw-list-item"><a href="https://tt.wikipedia.org/wiki/%D3%A8%D1%87%D0%BF%D0%BE%D1%87%D0%BC%D0%B0%D0%BA" title="Өчпочмак - tàtar" lang="tt" hreflang="tt" data-title="Өчпочмак" data-language-autonym="Татарча / tatarça" data-language-local-name="tàtar" class="interlanguage-link-target"><span>Татарча / tatarça</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%A2%D1%80%D0%B8%D0%BA%D1%83%D1%82%D0%BD%D0%B8%D0%BA" title="Трикутник - ucraïnès" lang="uk" hreflang="uk" data-title="Трикутник" data-language-autonym="Українська" data-language-local-name="ucraïnès" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-ur mw-list-item"><a href="https://ur.wikipedia.org/wiki/%D9%85%D8%AB%D9%84%D8%AB" title="مثلث - urdú" lang="ur" hreflang="ur" data-title="مثلث" data-language-autonym="اردو" data-language-local-name="urdú" class="interlanguage-link-target"><span>اردو</span></a></li><li class="interlanguage-link interwiki-uz mw-list-item"><a href="https://uz.wikipedia.org/wiki/Uchburchak" title="Uchburchak - uzbek" lang="uz" hreflang="uz" data-title="Uchburchak" data-language-autonym="Oʻzbekcha / ўзбекча" data-language-local-name="uzbek" class="interlanguage-link-target"><span>Oʻzbekcha / ўзбекча</span></a></li><li class="interlanguage-link interwiki-vec mw-list-item"><a href="https://vec.wikipedia.org/wiki/Triango%C5%82o" title="Triangoło - vènet" lang="vec" hreflang="vec" data-title="Triangoło" data-language-autonym="Vèneto" data-language-local-name="vènet" class="interlanguage-link-target"><span>Vèneto</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/Tam_gi%C3%A1c" title="Tam giác - vietnamita" lang="vi" hreflang="vi" data-title="Tam giác" data-language-autonym="Tiếng Việt" data-language-local-name="vietnamita" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-vls mw-list-item"><a href="https://vls.wikipedia.org/wiki/Drieoek" title="Drieoek - flamenc occidental" lang="vls" hreflang="vls" data-title="Drieoek" data-language-autonym="West-Vlams" data-language-local-name="flamenc occidental" class="interlanguage-link-target"><span>West-Vlams</span></a></li><li class="interlanguage-link interwiki-war mw-list-item"><a href="https://war.wikipedia.org/wiki/Trayanggulo" title="Trayanggulo - waray" lang="war" hreflang="war" data-title="Trayanggulo" data-language-autonym="Winaray" data-language-local-name="waray" class="interlanguage-link-target"><span>Winaray</span></a></li><li class="interlanguage-link interwiki-wuu mw-list-item"><a href="https://wuu.wikipedia.org/wiki/%E4%B8%89%E8%A7%92%E5%BD%A2" title="三角形 - xinès wu" lang="wuu" hreflang="wuu" data-title="三角形" data-language-autonym="吴语" data-language-local-name="xinès wu" class="interlanguage-link-target"><span>吴语</span></a></li><li class="interlanguage-link interwiki-yi mw-list-item"><a href="https://yi.wikipedia.org/wiki/%D7%93%D7%A8%D7%99%D7%99%D7%A2%D7%A7" title="דרייעק - ídix" lang="yi" hreflang="yi" data-title="דרייעק" data-language-autonym="ייִדיש" data-language-local-name="ídix" class="interlanguage-link-target"><span>ייִדיש</span></a></li><li class="interlanguage-link interwiki-yo mw-list-item"><a href="https://yo.wikipedia.org/wiki/An%C3%ADgunm%E1%BA%B9%CC%81ta" title="Anígunmẹ́ta - ioruba" lang="yo" hreflang="yo" data-title="Anígunmẹ́ta" data-language-autonym="Yorùbá" data-language-local-name="ioruba" class="interlanguage-link-target"><span>Yorùbá</span></a></li><li class="interlanguage-link interwiki-zgh mw-list-item"><a href="https://zgh.wikipedia.org/wiki/%E2%B4%B0%E2%B5%8E%E2%B4%BD%E2%B5%95%E2%B4%B0%E2%B4%B9" title="ⴰⵎⴽⵕⴰⴹ - amazic estàndard marroquí" lang="zgh" hreflang="zgh" data-title="ⴰⵎⴽⵕⴰⴹ" data-language-autonym="ⵜⴰⵎⴰⵣⵉⵖⵜ ⵜⴰⵏⴰⵡⴰⵢⵜ" data-language-local-name="amazic estàndard marroquí" class="interlanguage-link-target"><span>ⵜⴰⵎⴰⵣⵉⵖⵜ ⵜⴰⵏⴰⵡⴰⵢⵜ</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E4%B8%89%E8%A7%92%E5%BD%A2" title="三角形 - xinès" lang="zh" hreflang="zh" data-title="三角形" data-language-autonym="中文" data-language-local-name="xinès" class="interlanguage-link-target"><span>中文</span></a></li><li class="interlanguage-link interwiki-zh-classical mw-list-item"><a href="https://zh-classical.wikipedia.org/wiki/%E4%B8%89%E8%A7%92%E5%BD%A2" title="三角形 - xinès clàssic" lang="lzh" hreflang="lzh" data-title="三角形" data-language-autonym="文言" data-language-local-name="xinès clàssic" class="interlanguage-link-target"><span>文言</span></a></li><li class="interlanguage-link interwiki-zh-min-nan mw-list-item"><a href="https://zh-min-nan.wikipedia.org/wiki/Sa%E2%81%BF-kak-h%C3%AAng" title="Saⁿ-kak-hêng - xinès min del sud" lang="nan" hreflang="nan" data-title="Saⁿ-kak-hêng" data-language-autonym="閩南語 / Bân-lâm-gú" data-language-local-name="xinès min del sud" class="interlanguage-link-target"><span>閩南語 / Bân-lâm-gú</span></a></li><li class="interlanguage-link interwiki-zh-yue mw-list-item"><a href="https://zh-yue.wikipedia.org/wiki/%E4%B8%89%E8%A7%92%E5%BD%A2" title="三角形 - cantonès" lang="yue" hreflang="yue" data-title="三角形" data-language-autonym="粵語" data-language-local-name="cantonès" class="interlanguage-link-target"><span>粵語</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q19821#sitelinks-wikipedia" title="Modifica enllaços interlingües" class="wbc-editpage">Modifica els enllaços</a></span></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div class="vector-page-toolbar-container"> <div id="left-navigation"> <nav aria-label="Espais de noms"> <div id="p-associated-pages" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-associated-pages" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-nstab-main" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Triangle" title="Vegeu el contingut de la pàgina [c]" accesskey="c"><span>Pàgina</span></a></li><li id="ca-talk" class="vector-tab-noicon mw-list-item"><a href="/wiki/Discussi%C3%B3:Triangle" rel="discussion" title="Discussió sobre el contingut d&#039;aquesta pàgina [t]" accesskey="t"><span>Discussió</span></a></li> </ul> </div> </div> <div id="vector-variants-dropdown" class="vector-dropdown emptyPortlet" > <input type="checkbox" id="vector-variants-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-variants-dropdown" class="vector-dropdown-checkbox " aria-label="Canvia la variant de llengua" > <label id="vector-variants-dropdown-label" for="vector-variants-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">català</span> </label> <div class="vector-dropdown-content"> <div id="p-variants" class="vector-menu mw-portlet mw-portlet-variants emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> </div> </div> </nav> </div> <div id="right-navigation" class="vector-collapsible"> <nav aria-label="Vistes"> <div id="p-views" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-views" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-view" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Triangle"><span>Mostra</span></a></li><li id="ca-edit" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Triangle&amp;action=edit" title="Modifica el codi font d&#039;aquesta pàgina [e]" accesskey="e"><span>Modifica</span></a></li><li id="ca-history" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Triangle&amp;action=history" title="Versions antigues d&#039;aquesta pàgina [h]" accesskey="h"><span>Mostra l'historial</span></a></li> </ul> </div> </div> </nav> <nav class="vector-page-tools-landmark" aria-label="Eines de la pàgina"> <div id="vector-page-tools-dropdown" class="vector-dropdown vector-page-tools-dropdown" > <input type="checkbox" id="vector-page-tools-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-tools-dropdown" class="vector-dropdown-checkbox " aria-label="Eines" > <label id="vector-page-tools-dropdown-label" for="vector-page-tools-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">Eines</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-tools-unpinned-container" class="vector-unpinned-container"> <div id="vector-page-tools" class="vector-page-tools vector-pinnable-element"> <div class="vector-pinnable-header vector-page-tools-pinnable-header vector-pinnable-header-unpinned" data-feature-name="page-tools-pinned" data-pinnable-element-id="vector-page-tools" data-pinned-container-id="vector-page-tools-pinned-container" data-unpinned-container-id="vector-page-tools-unpinned-container" > <div class="vector-pinnable-header-label">Eines</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-page-tools.pin">mou a la barra lateral</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-page-tools.unpin">amaga</button> </div> <div id="p-cactions" class="vector-menu mw-portlet mw-portlet-cactions emptyPortlet vector-has-collapsible-items" title="Més opcions" > <div class="vector-menu-heading"> Accions </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-more-view" class="selected vector-more-collapsible-item mw-list-item"><a href="/wiki/Triangle"><span>Mostra</span></a></li><li id="ca-more-edit" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Triangle&amp;action=edit" title="Modifica el codi font d&#039;aquesta pàgina [e]" accesskey="e"><span>Modifica</span></a></li><li id="ca-more-history" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Triangle&amp;action=history"><span>Mostra l'historial</span></a></li> </ul> </div> </div> <div id="p-tb" class="vector-menu mw-portlet mw-portlet-tb" > <div class="vector-menu-heading"> General </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-whatlinkshere" class="mw-list-item"><a href="/wiki/Especial:Enlla%C3%A7os/Triangle" title="Una llista de totes les pàgines wiki que enllacen amb aquesta [j]" accesskey="j"><span>Què hi enllaça</span></a></li><li id="t-recentchangeslinked" class="mw-list-item"><a href="/wiki/Especial:Seguiment/Triangle" rel="nofollow" title="Canvis recents a pàgines enllaçades des d&#039;aquesta pàgina [k]" accesskey="k"><span>Canvis relacionats</span></a></li><li id="t-specialpages" class="mw-list-item"><a href="/wiki/Especial:P%C3%A0gines_especials" title="Llista totes les pàgines especials [q]" accesskey="q"><span>Pàgines especials</span></a></li><li id="t-permalink" class="mw-list-item"><a href="/w/index.php?title=Triangle&amp;oldid=34072757" title="Enllaç permanent a aquesta revisió de la pàgina"><span>Enllaç permanent</span></a></li><li id="t-info" class="mw-list-item"><a href="/w/index.php?title=Triangle&amp;action=info" title="Més informació sobre aquesta pàgina"><span>Informació de la pàgina</span></a></li><li id="t-cite" class="mw-list-item"><a href="/w/index.php?title=Especial:Citau&amp;page=Triangle&amp;id=34072757&amp;wpFormIdentifier=titleform" title="Informació sobre com citar aquesta pàgina"><span>Citau aquest article</span></a></li><li id="t-urlshortener" class="mw-list-item"><a href="/w/index.php?title=Especial:UrlShortener&amp;url=https%3A%2F%2Fca.wikipedia.org%2Fwiki%2FTriangle"><span>Obtén una URL abreujada</span></a></li><li id="t-urlshortener-qrcode" class="mw-list-item"><a href="/w/index.php?title=Especial:QrCode&amp;url=https%3A%2F%2Fca.wikipedia.org%2Fwiki%2FTriangle"><span>Descarrega el codi QR</span></a></li> </ul> </div> </div> <div id="p-coll-print_export" class="vector-menu mw-portlet mw-portlet-coll-print_export" > <div class="vector-menu-heading"> Imprimeix/exporta </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="coll-create_a_book" class="mw-list-item"><a href="/w/index.php?title=Especial:Llibre&amp;bookcmd=book_creator&amp;referer=Triangle"><span>Crea un llibre</span></a></li><li id="coll-download-as-rl" class="mw-list-item"><a href="/w/index.php?title=Especial:DownloadAsPdf&amp;page=Triangle&amp;action=show-download-screen"><span>Baixa com a PDF</span></a></li><li id="t-print" class="mw-list-item"><a href="/w/index.php?title=Triangle&amp;printable=yes" title="Versió per a impressió d&#039;aquesta pàgina [p]" accesskey="p"><span>Versió per a impressora</span></a></li> </ul> </div> </div> <div id="p-wikibase-otherprojects" class="vector-menu mw-portlet mw-portlet-wikibase-otherprojects" > <div class="vector-menu-heading"> En altres projectes </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="wb-otherproject-link wb-otherproject-commons mw-list-item"><a href="https://commons.wikimedia.org/wiki/Category:Triangles" hreflang="en"><span>Commons</span></a></li><li id="t-wikibase" class="wb-otherproject-link wb-otherproject-wikibase-dataitem mw-list-item"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q19821" title="Enllaç a l&#039;element del repositori de dades connectat [g]" accesskey="g"><span>Element a Wikidata</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> </div> </div> </div> <div class="vector-column-end"> <div class="vector-sticky-pinned-container"> <nav class="vector-page-tools-landmark" aria-label="Eines de la pàgina"> <div id="vector-page-tools-pinned-container" class="vector-pinned-container"> </div> </nav> <nav class="vector-appearance-landmark" aria-label="Aparença"> <div id="vector-appearance-pinned-container" class="vector-pinned-container"> <div id="vector-appearance" class="vector-appearance vector-pinnable-element"> <div class="vector-pinnable-header vector-appearance-pinnable-header vector-pinnable-header-pinned" data-feature-name="appearance-pinned" data-pinnable-element-id="vector-appearance" data-pinned-container-id="vector-appearance-pinned-container" data-unpinned-container-id="vector-appearance-unpinned-container" > <div class="vector-pinnable-header-label">Aparença</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-appearance.pin">mou a la barra lateral</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-appearance.unpin">amaga</button> </div> </div> </div> </nav> </div> </div> <div id="bodyContent" class="vector-body" aria-labelledby="firstHeading" data-mw-ve-target-container> <div class="vector-body-before-content"> <div class="mw-indicators"> </div> <div id="siteSub" class="noprint">De la Viquipèdia, l&#039;enciclopèdia lliure</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="ca" dir="ltr"><style data-mw-deduplicate="TemplateStyles:r34261971">.mw-parser-output .hatnote{width:100%;border-color:#77ccff;color:var(--color-base,#202122);background-color:#f5f5f5;margin-bottom:1em;font-style:italic}.mw-parser-output .hatnote i{font-style:normal}@media screen{html.skin-theme-clientpref-night .mw-parser-output .hatnote{color:var(--color-inverted,#fff);background-color:var(--background-color-inverted,#101418)}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .hatnote{color:var(--color-inverted,#fff);background-color:var(--background-color-inverted,#101418)}}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style> <table class="hatnote" cellspacing="5"> <tbody><tr> <td style="width: 25px; vertical-align: top;"><span typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Disambig_grey.svg/22px-Disambig_grey.svg.png" decoding="async" width="22" height="17" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Disambig_grey.svg/33px-Disambig_grey.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Disambig_grey.svg/44px-Disambig_grey.svg.png 2x" data-file-width="260" data-file-height="200" /></span></span> </td> <td>Aquest article tracta sobre la figura geomètrica. Vegeu-ne altres significats a «<a href="/wiki/Triangle_(desambiguaci%C3%B3)" class="mw-disambig" title="Triangle (desambiguació)">Triangle (desambiguació)</a>». </td></tr></tbody></table> <table class="infobox" style="font-size:90%;width:25em"><caption style="font-weight:bold;background:#b0d1ad"><span style="float:left;"><span typeof="mw:File"><span title="Infotaula de polítop"><img alt="Infotaula de polítop" src="//upload.wikimedia.org/wikipedia/commons/thumb/a/ae/Pyramid_icon.svg/22px-Pyramid_icon.svg.png" decoding="async" width="22" height="19" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/ae/Pyramid_icon.svg/33px-Pyramid_icon.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/ae/Pyramid_icon.svg/44px-Pyramid_icon.svg.png 2x" data-file-width="303" data-file-height="258" /></span></span></span>Triangle</caption><tbody><tr><td colspan="2" class="infobox-full-data infobox-data" style="text-align:center"><span typeof="mw:File"><a href="/w/index.php?title=Fitxer:Triangolo-Scaleno.svg&amp;lang=ca" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/d/da/Triangolo-Scaleno.svg/langca-300px-Triangolo-Scaleno.svg.png" decoding="async" width="300" height="180" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/da/Triangolo-Scaleno.svg/langca-450px-Triangolo-Scaleno.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/da/Triangolo-Scaleno.svg/langca-600px-Triangolo-Scaleno.svg.png 2x" data-file-width="150" data-file-height="90" /></a></span></td></tr><tr><th scope="row" class="infobox-label" style="text-align:left;background:#eeeeee">Tipus</th><td class="infobox-data"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q4903575" class="extiw" title="d:Special:EntityPage/Q4903575">polígon bicèntric</a>, <a href="/wiki/S%C3%ADmplex" title="Símplex">símplex</a>, <a href="https://www.wikidata.org/wiki/Special:EntityPage/Q85292517" class="extiw" title="d:Special:EntityPage/Q85292517">trítop</a>, <a href="/wiki/Pol%C3%ADgon" title="Polígon">polígon</a> i <a href="https://www.wikidata.org/wiki/Special:EntityPage/Q117307846" class="extiw" title="d:Special:EntityPage/Q117307846">planar generalized triangle</a> <sup>(en)</sup> <span class="mw-valign-baseline skin-invert" typeof="mw:File"><a href="https://www.wikidata.org/wiki/Q117307846?uselang=ca" title="Tradueix"><img alt="Tradueix" src="//upload.wikimedia.org/wikipedia/commons/thumb/7/70/Noun_Project_label_icon_1116097_cc_mirror.svg/10px-Noun_Project_label_icon_1116097_cc_mirror.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/70/Noun_Project_label_icon_1116097_cc_mirror.svg/15px-Noun_Project_label_icon_1116097_cc_mirror.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/70/Noun_Project_label_icon_1116097_cc_mirror.svg/20px-Noun_Project_label_icon_1116097_cc_mirror.svg.png 2x" data-file-width="158" data-file-height="161" /></a></span> <span class="penicon"><span class="mw-valign-baseline" typeof="mw:File"><a href="https://www.wikidata.org/wiki/Q19821?uselang=ca#P279" title="Modifica el valor a Wikidata"><img alt="Modifica el valor a Wikidata" src="//upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/10px-Arbcom_ru_editing.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/15px-Arbcom_ru_editing.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/20px-Arbcom_ru_editing.svg.png 2x" data-file-width="600" data-file-height="600" /></a></span></span></td></tr><tr><th scope="row" class="infobox-label" style="text-align:left;background:#eeeeee">Forma de les cares</th><td class="infobox-data"><a href="/wiki/Aresta_(geometria)" title="Aresta (geometria)">aresta</a> (3) <span class="penicon"><span class="mw-valign-baseline" typeof="mw:File"><a href="https://www.wikidata.org/wiki/Q19821?uselang=ca#P1312" title="Modifica el valor a Wikidata"><img alt="Modifica el valor a Wikidata" src="//upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/10px-Arbcom_ru_editing.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/15px-Arbcom_ru_editing.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/20px-Arbcom_ru_editing.svg.png 2x" data-file-width="600" data-file-height="600" /></a></span></span></td></tr><tr><th scope="row" class="infobox-label" style="text-align:left;background:#eeeeee"><a href="/wiki/Configuraci%C3%B3_de_v%C3%A8rtex" title="Configuració de vèrtex">Configuració de vèrtex</a></th><td class="infobox-data"><a href="/wiki/Segment_lineal" title="Segment lineal">segment</a> <span class="penicon"><span class="mw-valign-baseline" typeof="mw:File"><a href="https://www.wikidata.org/wiki/Q19821?uselang=ca#P1678" title="Modifica el valor a Wikidata"><img alt="Modifica el valor a Wikidata" src="//upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/10px-Arbcom_ru_editing.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/15px-Arbcom_ru_editing.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/20px-Arbcom_ru_editing.svg.png 2x" data-file-width="600" data-file-height="600" /></a></span></span></td></tr><tr><th colspan="2" class="infobox-header" style="text-align:center;background:#b0d1ad">Elements</th></tr><tr><td colspan="2" class="infobox-full-data infobox-data" style="text-align:center"></td></tr><tr><td style="background:#eeeeee;"><b>Arestes</b></td><td> 3<br /></td></tr><tr><td colspan="2"> </td></tr><tr><td style="background:#eeeeee;"><b>Vèrtexs</b></td><td> 3<br /></td></tr><tr><td style="background:#eeeeee;"><b>Bases</b></td><td> <br /></td></tr><tr><td colspan="2"> </td></tr><tr><td style="background:#eeeeee;"><b>Altures</b></td><td> <br /></td></tr><tr><td style="background:#eeeeee;"><b>Apex</b></td><td> <br /></td></tr><tr><td colspan="2"> </td></tr><tr><td style="background:#eeeeee;"><b>Apex-base pair</b></td><td> 3 <span class="penicon"><span class="mw-valign-baseline" typeof="mw:File"><a href="https://www.wikidata.org/wiki/Q19821?uselang=ca#P2670" title="Modifica el valor a Wikidata"><img alt="Modifica el valor a Wikidata" src="//upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/10px-Arbcom_ru_editing.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/15px-Arbcom_ru_editing.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/20px-Arbcom_ru_editing.svg.png 2x" data-file-width="600" data-file-height="600" /></a></span></span></td></tr><tr><th colspan="2" class="infobox-header" style="text-align:center;background:#b0d1ad">Sèrie</th></tr><tr><td colspan="2" class="infobox-full-data infobox-data" style="text-align:center"><div style="float: left;">&#8592; <a href="https://www.wikidata.org/wiki/Special:EntityPage/Q854818" class="extiw" title="d:Special:EntityPage/Q854818">dígon</a> i <a href="/wiki/Segment_lineal" title="Segment lineal">segment</a> <span class="penicon"><span class="mw-valign-baseline" typeof="mw:File"><a href="https://www.wikidata.org/wiki/Q19821?uselang=ca#P155" title="Modifica el valor a Wikidata"><img alt="Modifica el valor a Wikidata" src="//upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/10px-Arbcom_ru_editing.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/15px-Arbcom_ru_editing.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/20px-Arbcom_ru_editing.svg.png 2x" data-file-width="600" data-file-height="600" /></a></span></span> </div><div style="float: right;"><a href="/wiki/Quadril%C3%A0ter" title="Quadrilàter">quadrilàter</a> i <a href="/wiki/Tetr%C3%A0edre" title="Tetràedre">tetràedre</a> <span class="penicon"><span class="mw-valign-baseline" typeof="mw:File"><a href="https://www.wikidata.org/wiki/Q19821?uselang=ca#P156" title="Modifica el valor a Wikidata"><img alt="Modifica el valor a Wikidata" src="//upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/10px-Arbcom_ru_editing.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/15px-Arbcom_ru_editing.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/20px-Arbcom_ru_editing.svg.png 2x" data-file-width="600" data-file-height="600" /></a></span></span> &#8594;</div></td></tr><tr><th colspan="2" class="infobox-header" style="text-align:center;background:#b0d1ad">Més informació</th></tr><tr><th scope="row" class="infobox-label" style="text-align:left;background:#eeeeee"><a href="/wiki/MathWorld" title="MathWorld">MathWorld</a></th><td class="infobox-data"><a rel="nofollow" class="external text" href="http://mathworld.wolfram.com/Triangle.html">Triangle</a> <span class="penicon"><span class="mw-valign-baseline" typeof="mw:File"><a href="https://www.wikidata.org/wiki/Q19821?uselang=ca#P2812" title="Modifica el valor a Wikidata"><img alt="Modifica el valor a Wikidata" src="//upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/10px-Arbcom_ru_editing.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/15px-Arbcom_ru_editing.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/20px-Arbcom_ru_editing.svg.png 2x" data-file-width="600" data-file-height="600" /></a></span></span></td></tr></tbody></table> <p>Un <b>triangle</b> és un <a href="/wiki/Pol%C3%ADgon" title="Polígon">polígon</a> de tres costats. En <a href="/wiki/Geometria_euclidiana" title="Geometria euclidiana">geometria euclidiana</a> tres <a href="/wiki/Punt_(geometria)" title="Punt (geometria)">punts</a> diferents no alineats defineixen sempre un únic pla i un únic triangle.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">&#91;</span>1<span class="cite-bracket">&#93;</span></a></sup> La branca de les <a href="/wiki/Matem%C3%A0tiques" title="Matemàtiques">matemàtiques</a> que tracta les relacions internes dels triangles és la <a href="/wiki/Trigonometria" title="Trigonometria">trigonometria</a>. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Història"><span id="Hist.C3.B2ria"></span>Història</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=1" title="Modifica la secció: Història"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/Fitxer:Egyptian_A%27h-mos%C3%A8_or_Rhind_Papyrus_(1065x1330).png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/4/4b/Egyptian_A%27h-mos%C3%A8_or_Rhind_Papyrus_%281065x1330%29.png/220px-Egyptian_A%27h-mos%C3%A8_or_Rhind_Papyrus_%281065x1330%29.png" decoding="async" width="220" height="275" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/4b/Egyptian_A%27h-mos%C3%A8_or_Rhind_Papyrus_%281065x1330%29.png/330px-Egyptian_A%27h-mos%C3%A8_or_Rhind_Papyrus_%281065x1330%29.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/4b/Egyptian_A%27h-mos%C3%A8_or_Rhind_Papyrus_%281065x1330%29.png/440px-Egyptian_A%27h-mos%C3%A8_or_Rhind_Papyrus_%281065x1330%29.png 2x" data-file-width="1065" data-file-height="1330" /></a><figcaption>Problemes R49→R55 del <a href="/wiki/Papir_de_Rhind" title="Papir de Rhind">papir de Rhind</a></figcaption></figure> <p>No s'ha conservat cap document matemàtic del <a href="/wiki/Regne_Antic_d%27Egipte" title="Regne Antic d&#39;Egipte">Regne Antic d'Egipte</a>. Però l'arquitectura monumental de les dinasties <a href="/wiki/Dinastia_III_d%27Egipte" title="Dinastia III d&#39;Egipte">III</a> i <a href="/wiki/Dinastia_IV_d%27Egipte" title="Dinastia IV d&#39;Egipte">IV</a> constitueix una prova destacable que els egipcis d'aquesta època tenien coneixements relativament elaborats en geometria, i en particular en l'estudi dels triangles. </p> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/Fitxer:Triangle-R51-Papyrus-rhind.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/4/41/Triangle-R51-Papyrus-rhind.jpg/220px-Triangle-R51-Papyrus-rhind.jpg" decoding="async" width="220" height="113" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/41/Triangle-R51-Papyrus-rhind.jpg/330px-Triangle-R51-Papyrus-rhind.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/41/Triangle-R51-Papyrus-rhind.jpg/440px-Triangle-R51-Papyrus-rhind.jpg 2x" data-file-width="643" data-file-height="331" /></a><figcaption>figura del triangle representat en el problema R51 del <a href="/wiki/Papir_de_Rhind" title="Papir de Rhind">papir de Rhind</a></figcaption></figure> <p>El càlcul de l'àrea del triangle s'estudia en els problemes R51 del <a href="/wiki/Papir_de_Rhind" title="Papir de Rhind">papir de Rhind</a>, M4, M7 i M17 del <a href="/wiki/Papir_de_Moscou" title="Papir de Moscou">papir de Moscou</a> que daten tots dos del <a href="/wiki/Regne_Mitj%C3%A0" class="mw-redirect" title="Regne Mitjà">Regne Mitjà</a>. En la història mundial de les matemàtiques, el problema R51 constitueix el primer testimoni escrit que tracta del càlcul de l'àrea d'un triangle. </p> <dl><dt>Enunciat del problema R51 del <a href="/wiki/Papir_de_Rhind" title="Papir de Rhind">papir de Rhind</a></dt> <dd><sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">&#91;</span>2<span class="cite-bracket">&#93;</span></a></sup></dd></dl> <div style="clear:&#123;&#123;#switch:left&#124;center=both&#124;#default=left;"> <table style="margin:auto; width:auto; border-collapse:collapse; border-style:none;"> <tbody><tr> <td width="20" valign="top" style="font-size:35px; padding:0 10px; text-align:left; font-family:&#39;Times New Roman&#39;, serif; font-weight:bold; color:silver;">« </td> <td valign="middle" align="left" style="">Exemple de càlcul d'un triangle de terra. Si algú us diu: Un triangle de 10 khet sobre el seu mryt i de 4 khet sobre la seva base. Quina és la seva superfície? Calculau la meitat de 4, que són 2, per fer-ne un rectangle. Llavors feu la multiplicació de 10 per 2. Aquesta n'és la superfície. </td> <td width="20" valign="bottom" style="font-size:35px; padding:0 10px 10px; text-align:right; font-family:&#39;Times New Roman&#39;, serif; font-weight:bold; color:silver;">» </td></tr></tbody></table></div> <p>El terme mryt significa probablement alçada, o costat. Però la fórmula utilitzada per al càlcul de l'àrea fa inclinar la interpretació a favor de la primera solució.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">&#91;</span>3<span class="cite-bracket">&#93;</span></a></sup> L'escriba prenia la meitat de la base del triangle i calculava l'àrea del rectangle format per aquest costat i l'alçada, sigui </p> <center><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle A={\frac {base}{2}}{mryt}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>A</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mi>b</mi> <mi>a</mi> <mi>s</mi> <mi>e</mi> </mrow> <mn>2</mn> </mfrac> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mi>m</mi> <mi>r</mi> <mi>y</mi> <mi>t</mi> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle A={\frac {base}{2}}{mryt}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/00195f51c9d29b1d20a1f2c1c6db7f8ab8544912" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:15.163ex; height:5.343ex;" alt="{\displaystyle A={\frac {base}{2}}{mryt}}"></span></center> <p>Equival a la fórmula general que es fa servir actualment&#160;: </p> <center><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle S={\frac {ah}{2}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>S</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mi>a</mi> <mi>h</mi> </mrow> <mn>2</mn> </mfrac> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle S={\frac {ah}{2}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/9dfc5d536cd9b36167ec3021267e6e3bf4199872" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:8.003ex; height:5.343ex;" alt="{\displaystyle S={\frac {ah}{2}}}"></span></center> <p>El fet que un triangle de costats 3-4-5 és rectangle també era conegut dels antics Egipcis i Mesopotàmics. <a href="/wiki/Euclides" title="Euclides">Euclides</a>, al llibre I dels seus <a href="/wiki/Elements_d%27Euclides" title="Elements d&#39;Euclides">Elements</a>, cap a 300&#160;aC, enuncia la propietat de la suma dels angles del triangle i els tres casos d'igualtat dels triangles. </p> <div class="mw-heading mw-heading2"><h2 id="Tipus_de_triangles">Tipus de triangles</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=2" title="Modifica la secció: Tipus de triangles"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Classificació_segons_els_costats"><span id="Classificaci.C3.B3_segons_els_costats"></span>Classificació segons els costats</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=3" title="Modifica la secció: Classificació segons els costats"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Els triangles es poden classificar segons la longitud dels seus costats:<sup id="cite_ref-gamma2_4-0" class="reference"><a href="#cite_note-gamma2-4"><span class="cite-bracket">&#91;</span>4<span class="cite-bracket">&#93;</span></a></sup> </p> <ul><li><a href="/wiki/Triangle_equil%C3%A0ter" title="Triangle equilàter">Triangle equilàter</a> és aquell en què tots tres costats tenen la mateixa llargada. Un triangle equilàter també és <b>equiangular</b>, és a dir, tots els seus angles interns són iguals (60&#160;graus).</li> <li><a href="/wiki/Triangle_is%C3%B2sceles" title="Triangle isòsceles">Triangle isòsceles</a> és aquell en què dos dels costats són iguals. Un triangle isòsceles també té dos angles interns iguals.</li> <li><a href="/wiki/Triangle_escal%C3%A8" title="Triangle escalè">Triangle escalè</a> és el que té tots els costats de diferent longitud. Els angles interns d'un triangle escalè són tots diferents.</li></ul> <ul class="gallery mw-gallery-traditional"> <li class="gallerybox" style="width: 155px"> <div class="thumb" style="width: 150px; height: 150px;"><span typeof="mw:File"><a href="/wiki/Fitxer:Equilateral_Triangle.svg" class="mw-file-description" title="Triangle equilàter"><img alt="Triangle equilàter" src="//upload.wikimedia.org/wikipedia/commons/thumb/f/fc/Equilateral_Triangle.svg/120px-Equilateral_Triangle.svg.png" decoding="async" width="120" height="113" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/fc/Equilateral_Triangle.svg/180px-Equilateral_Triangle.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/fc/Equilateral_Triangle.svg/240px-Equilateral_Triangle.svg.png 2x" data-file-width="616" data-file-height="582" /></a></span></div> <div class="gallerytext">Triangle equilàter</div> </li> <li class="gallerybox" style="width: 155px"> <div class="thumb" style="width: 150px; height: 150px;"><span typeof="mw:File"><a href="/wiki/Fitxer:Triangle.Isosceles.svg" class="mw-file-description" title="Triangle isòsceles"><img alt="Triangle isòsceles" src="//upload.wikimedia.org/wikipedia/commons/thumb/1/14/Triangle.Isosceles.svg/78px-Triangle.Isosceles.svg.png" decoding="async" width="78" height="120" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/1/14/Triangle.Isosceles.svg/117px-Triangle.Isosceles.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/1/14/Triangle.Isosceles.svg/156px-Triangle.Isosceles.svg.png 2x" data-file-width="74" data-file-height="114" /></a></span></div> <div class="gallerytext">Triangle isòsceles</div> </li> <li class="gallerybox" style="width: 155px"> <div class="thumb" style="width: 150px; height: 150px;"><span typeof="mw:File"><a href="/wiki/Fitxer:Triangle.Scalene.svg" class="mw-file-description" title="Triangle escalè"><img alt="Triangle escalè" src="//upload.wikimedia.org/wikipedia/commons/thumb/9/93/Triangle.Scalene.svg/120px-Triangle.Scalene.svg.png" decoding="async" width="120" height="54" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/93/Triangle.Scalene.svg/180px-Triangle.Scalene.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/93/Triangle.Scalene.svg/240px-Triangle.Scalene.svg.png 2x" data-file-width="245" data-file-height="110" /></a></span></div> <div class="gallerytext">Triangle escalè</div> </li> </ul> <div class="mw-heading mw-heading3"><h3 id="Classificació_segons_els_angles"><span id="Classificaci.C3.B3_segons_els_angles"></span>Classificació segons els angles</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=4" title="Modifica la secció: Classificació segons els angles"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Els triangles també es poden classificar segons els seus angles:<sup id="cite_ref-gamma2_4-1" class="reference"><a href="#cite_note-gamma2-4"><span class="cite-bracket">&#91;</span>4<span class="cite-bracket">&#93;</span></a></sup> </p> <ul><li><a href="/wiki/Triangle_rectangle" title="Triangle rectangle">Triangle rectangle</a> té un angle intern de 90&#160;graus (<a href="/wiki/Angle_recte" class="mw-redirect" title="Angle recte">angle recte</a>). El costat oposat a l'angle recte és la <i><a href="/wiki/Hipotenusa" title="Hipotenusa">hipotenusa</a></i>, que és el costat més llarg del triangle rectangle. Els altres dos costats es diuen <i><a href="/wiki/Catet" title="Catet">catets</a></i>.</li> <li><b>Triangle obtusangle</b> té un angle intern de més de 90&#160;graus (<a href="/wiki/Angle_obt%C3%BAs" class="mw-redirect" title="Angle obtús">angle obtús</a>).</li> <li><b>Triangle acutangle</b> té els tres angles interns de menys de 90&#160;graus (<a href="/wiki/Angle_agut" class="mw-redirect" title="Angle agut">angles aguts</a>).</li></ul> <ul class="gallery mw-gallery-traditional"> <li class="gallerybox" style="width: 155px"> <div class="thumb" style="width: 150px; height: 150px;"><span typeof="mw:File"><a href="/wiki/Fitxer:Triangolo-Rettangolo.svg" class="mw-file-description" title="Triangle rectangle"><img alt="Triangle rectangle" src="//upload.wikimedia.org/wikipedia/commons/thumb/9/93/Triangolo-Rettangolo.svg/113px-Triangolo-Rettangolo.svg.png" decoding="async" width="113" height="120" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/93/Triangolo-Rettangolo.svg/169px-Triangolo-Rettangolo.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/93/Triangolo-Rettangolo.svg/225px-Triangolo-Rettangolo.svg.png 2x" data-file-width="606" data-file-height="646" /></a></span></div> <div class="gallerytext">Triangle rectangle</div> </li> <li class="gallerybox" style="width: 155px"> <div class="thumb" style="width: 150px; height: 150px;"><span typeof="mw:File"><a href="/wiki/Fitxer:Triangle.Obtuse.svg" class="mw-file-description" title="Triangle obtusangle"><img alt="Triangle obtusangle" src="//upload.wikimedia.org/wikipedia/commons/thumb/0/05/Triangle.Obtuse.svg/120px-Triangle.Obtuse.svg.png" decoding="async" width="120" height="120" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/05/Triangle.Obtuse.svg/180px-Triangle.Obtuse.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/05/Triangle.Obtuse.svg/240px-Triangle.Obtuse.svg.png 2x" data-file-width="113" data-file-height="113" /></a></span></div> <div class="gallerytext">Triangle obtusangle</div> </li> <li class="gallerybox" style="width: 155px"> <div class="thumb" style="width: 150px; height: 150px;"><span typeof="mw:File"><a href="/wiki/Fitxer:Triangle.Acute.svg" class="mw-file-description" title="Triangle acutangle"><img alt="Triangle acutangle" src="//upload.wikimedia.org/wikipedia/commons/thumb/e/ed/Triangle.Acute.svg/120px-Triangle.Acute.svg.png" decoding="async" width="120" height="74" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/e/ed/Triangle.Acute.svg/180px-Triangle.Acute.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/e/ed/Triangle.Acute.svg/240px-Triangle.Acute.svg.png 2x" data-file-width="794" data-file-height="491" /></a></span></div> <div class="gallerytext">Triangle acutangle</div> </li> </ul> <div class="mw-heading mw-heading2"><h2 id="Punts,_línies_i_cercles_associats_a_un_triangle"><span id="Punts.2C_l.C3.ADnies_i_cercles_associats_a_un_triangle"></span>Punts, línies i cercles associats a un triangle</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=5" title="Modifica la secció: Punts, línies i cercles associats a un triangle"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Mitjanes_i_centre_de_gravetat">Mitjanes i centre de gravetat</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=6" title="Modifica la secció: Mitjanes i centre de gravetat"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size mw-halign-left" typeof="mw:File/Thumb"><a href="/wiki/Fitxer:Triangle.Centroid.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/5/5e/Triangle.Centroid.svg/220px-Triangle.Centroid.svg.png" decoding="async" width="220" height="178" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/5e/Triangle.Centroid.svg/330px-Triangle.Centroid.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/5e/Triangle.Centroid.svg/440px-Triangle.Centroid.svg.png 2x" data-file-width="809" data-file-height="654" /></a><figcaption>Medianes i baricentre d'un triangle</figcaption></figure> <style data-mw-deduplicate="TemplateStyles:r30997230">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}</style><div role="note" class="hatnote navigation-not-searchable">Article principal: <a href="/wiki/Mitjana_(geometria)" title="Mitjana (geometria)">Mitjana (geometria)</a></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r30997230"><div role="note" class="hatnote navigation-not-searchable">Article principal: <a href="/wiki/Baricentre" title="Baricentre">Baricentre</a></div> <p>Es diu <b>mitjana</b> d'un triangle cadascuna de les tres rectes que passen per un vèrtex del triangle i pel punt mitjà del costat oposat a aquest vèrtex. Cadascuna de les tres medianes divideix el triangle en dos triangles d'àrees iguals. Les tres medianes d'un triangle són concurrents. El seu punt d'intersecció <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle G\,}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>G</mi> <mspace width="thinmathspace" /> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle G\,}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/a1f6c4d01b8be460cde4156d1fde6af720f8ff12" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.214ex; height:2.176ex;" alt="{\displaystyle G\,}"></span> s'anomena <b><a href="/wiki/Centre_de_gravetat" title="Centre de gravetat">centre de gravetat</a></b> o <b>baricentre</b> del triangle. Si el triangle fos una placa sòlida homogènia, podria sostenir-se en equilibri sobre una punta posant-la exactament per aquest punt <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle G}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>G</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle G}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/f5f3c8921a3b352de45446a6789b104458c9f90b" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.827ex; height:2.176ex;" alt="{\displaystyle G}"></span>. </p><p>El centre de gravetat del triangle també és el centre de gravetat dels vèrtexs. La distància entre el baricentre i un vèrtex és 2/3 de la distància entre el vèrtex i el punt mitjà del costat oposat. <br style="clear:both;" /> </p> <div class="mw-heading mw-heading3"><h3 id="Mediatrius_i_circumferència_circumscrita"><span id="Mediatrius_i_circumfer.C3.A8ncia_circumscrita"></span>Mediatrius i circumferència circumscrita</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=7" title="Modifica la secció: Mediatrius i circumferència circumscrita"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure typeof="mw:File/Frame"><a href="/wiki/Fitxer:Triangle.Circumcenter.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/7/74/Triangle.Circumcenter.svg/198px-Triangle.Circumcenter.svg.png" decoding="async" width="198" height="198" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/74/Triangle.Circumcenter.svg/297px-Triangle.Circumcenter.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/74/Triangle.Circumcenter.svg/396px-Triangle.Circumcenter.svg.png 2x" data-file-width="198" data-file-height="198" /></a><figcaption>Mediatrius, circumferència circumscrita i circumcentre d'un triangle.</figcaption></figure> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r30997230"><div role="note" class="hatnote navigation-not-searchable">Article principal: <a href="/wiki/Circumfer%C3%A8ncia_circumscrita" title="Circumferència circumscrita">Circumferència circumscrita</a></div> <p>S'anomena <b>mediatriu</b> d'un triangle cada una de les <a href="/wiki/Mediatriu" title="Mediatriu">mediatrius</a> dels costats. </p><p>Com que la mediatriu d'un segment és el lloc geomètric dels punts equidistants dels extrems del segment, el punt on es tallen dues de les mediatrius del triangle és equidistant dels tres vèrtexs, per tant és el centre de la circumferència que passa per tots tres i pertany a la tercera mediatriu. </p><p>Es pot afirmar que: </p> <ul><li>Un triangle és obtusangle si i només si el seu circumcentre és exterior al triangle</li> <li>Un triangle és acutangle si i només si el seu circumcentre és interior al triangle</li> <li>Un triangle és rectangle si i només si el seu circumcentre és en un costat del triangle.</li></ul> <p><br style="clear:both;" /> </p> <div class="mw-heading mw-heading3"><h3 id="Bisectrius_i_circumferència_inscrita"><span id="Bisectrius_i_circumfer.C3.A8ncia_inscrita"></span>Bisectrius i circumferència inscrita</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=8" title="Modifica la secció: Bisectrius i circumferència inscrita"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size mw-halign-left" typeof="mw:File/Thumb"><a href="/wiki/Fitxer:Triangle.Incircle.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/0/0c/Triangle.Incircle.svg/220px-Triangle.Incircle.svg.png" decoding="async" width="220" height="190" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/0c/Triangle.Incircle.svg/330px-Triangle.Incircle.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/0c/Triangle.Incircle.svg/440px-Triangle.Incircle.svg.png 2x" data-file-width="182" data-file-height="157" /></a><figcaption>Un triangle (negre) amb la circumferència inscrita, l'incentre i les bisectrius internes.</figcaption></figure> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r30997230"><div role="note" class="hatnote navigation-not-searchable">Article principal: <a href="/wiki/Incentre" title="Incentre">Incentre</a></div> <p>Les <b>bisectrius</b> d'un triangle són les tres <a href="/wiki/Bisectriu" title="Bisectriu">bisectrius</a> interiors dels seus angles. </p><p>La <b>circumferència inscrita</b> és la circumferència que és tangent als tres costats del triangle i el seu centre és l'<b>incentre</b> del triangle. </p><p>La bisectriu d'un angle té la propietat de ser el lloc geomètric del centre de les circumferències que són tangents simultàniament als dos costats adjacents de l'angle, per tant el punt on es troben dues de les bisectrius és el centre de la circumferència que és tangent als tres costats del triangle, i per això la tercera bisectriu també ha de passar per aquest punt. <br style="clear:both;" /> </p> <div class="mw-heading mw-heading3"><h3 id="Altures_i_ortocentre">Altures i ortocentre</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=9" title="Modifica la secció: Altures i ortocentre"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure typeof="mw:File/Frame"><a href="/wiki/Fitxer:Triangle.Orthocenter.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/9/93/Triangle.Orthocenter.svg/182px-Triangle.Orthocenter.svg.png" decoding="async" width="182" height="146" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/93/Triangle.Orthocenter.svg/273px-Triangle.Orthocenter.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/93/Triangle.Orthocenter.svg/364px-Triangle.Orthocenter.svg.png 2x" data-file-width="182" data-file-height="146" /></a><figcaption>Altures i ortocentre d'un triangle</figcaption></figure> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r30997230"><div role="note" class="hatnote navigation-not-searchable">Article principal: <a href="/w/index.php?title=Altura_(triangle)&amp;action=edit&amp;redlink=1" class="new" title="Altura (triangle) (encara no existeix)">Altura (triangle)</a></div> <p>Les altures d'un triangle són cadascuna de les tres rectes que passen per un dels seus vertex i són perpendiculars al costat oposat.<sup id="cite_ref-gamma2_4-2" class="reference"><a href="#cite_note-gamma2-4"><span class="cite-bracket">&#91;</span>4<span class="cite-bracket">&#93;</span></a></sup> L&#39;<b>ortocentre</b> d'un triangle és el punt on es troben les tres altures. </p><p>Propietats&#160;: </p> <ul><li>Un triangle és rectangle si el seu ortocentre és un dels seus vèrtexs</li> <li>Un triangle és obtusangle si i només si el seu ortocentre és exterior al triangle</li> <li>Un triangle és acutangle si i només si el seu ortocentre és interior al triangle</li> <li>Cada vèrtex del triangle és l'ortocentre del triangle format pels altres dos vèrtexs i l'ortocentre del triangle original.</li></ul> <div class="mw-heading mw-heading3"><h3 id="Recta_i_cercle_d'Euler"><span id="Recta_i_cercle_d.27Euler"></span>Recta i cercle d'Euler</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=10" title="Modifica la secció: Recta i cercle d&#039;Euler"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-halign-left" typeof="mw:File/Frame"><a href="/wiki/Fitxer:Triangle.NinePointCircle.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/5/5f/Triangle.NinePointCircle.svg/182px-Triangle.NinePointCircle.svg.png" decoding="async" width="182" height="147" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/5f/Triangle.NinePointCircle.svg/273px-Triangle.NinePointCircle.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/5f/Triangle.NinePointCircle.svg/364px-Triangle.NinePointCircle.svg.png 2x" data-file-width="182" data-file-height="147" /></a><figcaption>Circumferència dels nou punts.</figcaption></figure> <figure typeof="mw:File/Frame"><a href="/wiki/Fitxer:Triangle.EulerLine.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Triangle.EulerLine.svg/520px-Triangle.EulerLine.svg.png" decoding="async" width="520" height="420" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Triangle.EulerLine.svg/780px-Triangle.EulerLine.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/65/Triangle.EulerLine.svg/1040px-Triangle.EulerLine.svg.png 2x" data-file-width="520" data-file-height="420" /></a><figcaption>Recta d'Euler.</figcaption></figure> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r30997230"><div role="note" class="hatnote navigation-not-searchable">Article principal: <a href="/wiki/Recta_d%27Euler" title="Recta d&#39;Euler">Recta d'Euler</a></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r30997230"><div role="note" class="hatnote navigation-not-searchable">Article principal: <a href="/wiki/Circumfer%C3%A8ncia_dels_nou_punts" title="Circumferència dels nou punts">Circumferència dels nou punts</a></div> <p>L'<a href="/wiki/Ortocentre" title="Ortocentre">ortocentre</a>, el <a href="/wiki/Circumcentre" class="mw-redirect" title="Circumcentre">circumcentre</a> i el <a href="/wiki/Baricentre" title="Baricentre">baricentre</a> d'un <b>triangle</b> són col·lineals (en el cas particular del triangle equilàter, tots tres coincideixen en el mateix punt, per tant hi ha infinites rectes que els contenen a tots tres). La recta que els conté es diu <b>recta d'Euler</b> en honor del matemàtic suís <a href="/wiki/Leonhard_Euler" title="Leonhard Euler">Leonhard Euler</a> el qual va descobrir aquest fet a mitjan segle&#160;<span title="Nombre&#160;escrit en xifres romanes" style="font-variant:small-caps;">xviii</span>. </p><p>La <b>circumferència dels nou punts</b>, anomenada també <b>circumferència d'Euler</b> és una <a href="/wiki/Circumfer%C3%A8ncia" title="Circumferència">circumferència</a> associada a cada triangle que passa per nou <a href="/wiki/Punt_(geometria)" title="Punt (geometria)">punts</a> notables. Aquests punts són:<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">&#91;</span>5<span class="cite-bracket">&#93;</span></a></sup> </p> <ul><li>El <a href="/wiki/Punt_mitj%C3%A0" title="Punt mitjà">punt mitjà</a> de cada costat del triangle.</li> <li>Els peus de les alçades</li> <li>Els punts mitjans dels segments determinats per l'<a href="/wiki/Ortocentre" title="Ortocentre">ortocentre</a> i els <a href="/wiki/V%C3%A8rtex_(geometria)" title="Vèrtex (geometria)">vèrtexs</a> del triangle.</li></ul> <div class="mw-heading mw-heading2"><h2 id="Superfície"><span id="Superf.C3.ADcie"></span>Superfície</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=11" title="Modifica la secció: Superfície"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li>La <a href="/wiki/Superf%C3%ADcie" class="mw-redirect" title="Superfície">superfície</a> d'un triangle s'obté multiplicant la base per l'alçada (on l'alçada és un segment perpendicular que parteix de la base fins al vèrtex oposat) i dividint entre dos.</li></ul> <dl><dd><i>A</i> = (<i>b</i>⋅<i>h</i>)/2.</dd></dl> <figure class="mw-default-size mw-halign-left" typeof="mw:File/Thumb"><a href="/wiki/Fitxer:Triangle.GeometryArea.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/a/a5/Triangle.GeometryArea.svg/220px-Triangle.GeometryArea.svg.png" decoding="async" width="220" height="55" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/a5/Triangle.GeometryArea.svg/330px-Triangle.GeometryArea.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/a5/Triangle.GeometryArea.svg/440px-Triangle.GeometryArea.svg.png 2x" data-file-width="504" data-file-height="126" /></a><figcaption>Demostració gràfica de la fórmula de la superfície d'un triangle per mitjà d'obtenir un paral·lelogram d'àrea doble</figcaption></figure> <figure typeof="mw:File/Frame"><a href="/wiki/Fitxer:%C3%80rea_del_triangle_partint-lo_en_dos_triangles_rectangles.PNG" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/1/1c/%C3%80rea_del_triangle_partint-lo_en_dos_triangles_rectangles.PNG" decoding="async" width="228" height="125" class="mw-file-element" data-file-width="228" data-file-height="125" /></a><figcaption>Demostració gràfica de la fórmula de la superfície d'un triangle descomponent-lo en dos triangles rectangles.</figcaption></figure> <p>Tot i que és senzilla, aquesta fórmula només és útil si es coneix l'altura. Per exemple per a mesurar l'àrea d'un camp triangular és fàcil mesurar la longitud de cada costat, però per a poder aplicar aquesta fórmula, cal trobar l'altura i això no és fàcil a la pràctica perquè s'ha de traçar una perpendicular a un costat que passi per un vèrtex i la distància entre el vèrtex i el costat pot ser gran. Hi ha fórmules que permeten trobar l'àrea del triangle sense saber l'altura. Tot seguit es presenten les que es fan servir més sovint<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">&#91;</span>6<span class="cite-bracket">&#93;</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Fent_servir_vectors">Fent servir vectors</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=12" title="Modifica la secció: Fent servir vectors"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-halign-left" typeof="mw:File/Frame"><a href="/wiki/Fitxer:%C3%80rea_d%27un_triangle_fent_servir_vectors.PNG" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/c/c8/%C3%80rea_d%27un_triangle_fent_servir_vectors.PNG" decoding="async" width="266" height="142" class="mw-file-element" data-file-width="266" data-file-height="142" /></a><figcaption>L'àrea d'un triangle calculada fent servir vectors.</figcaption></figure> <p>L'àrea d'un paral·lelogram definit per dos vectors <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\overrightarrow {u}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <mover> <mi>u</mi> <mo>&#x2192;<!-- → --></mo> </mover> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle {\overrightarrow {u}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/ce70b04c12b0575de787a71dac4239e911e9cdf6" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.388ex; height:3.009ex;" alt="{\displaystyle {\overrightarrow {u}}}"></span>, <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\overrightarrow {v}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <mover> <mi>v</mi> <mo>&#x2192;<!-- → --></mo> </mover> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle {\overrightarrow {v}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/cdbb1a68c861cbd0cfda4f71510f67eed27c7cb1" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.388ex; height:3.009ex;" alt="{\displaystyle {\overrightarrow {v}}}"></span> és la norma del seu <a href="/wiki/Producte_vectorial" title="Producte vectorial">producte vectorial</a>&#160;: </p> <center><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle A_{p}=\left\|{{\overrightarrow {u}}\wedge {\overrightarrow {v}}}\right\|}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>A</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>p</mi> </mrow> </msub> <mo>=</mo> <mrow> <mo symmetric="true">&#x2016;</mo> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mover> <mi>u</mi> <mo>&#x2192;<!-- → --></mo> </mover> </mrow> <mo>&#x2227;<!-- ∧ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mover> <mi>v</mi> <mo>&#x2192;<!-- → --></mo> </mover> </mrow> </mrow> <mo symmetric="true">&#x2016;</mo> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle A_{p}=\left\|{{\overrightarrow {u}}\wedge {\overrightarrow {v}}}\right\|}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/015e895a6ef2654e262548d41ca81b868e4faa49" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.671ex; width:15.585ex; height:4.343ex;" alt="{\displaystyle A_{p}=\left\|{{\overrightarrow {u}}\wedge {\overrightarrow {v}}}\right\|}"></span>.</center> <p>Per tant, es pot calcular l'àrea d'un triangle a partir d'aquesta fórmula: </p> <center><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle A={\frac {1}{2}}\left\|{{\overrightarrow {AB}}\wedge {\overrightarrow {AC}}}\right\|}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>A</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </mrow> <mrow> <mo symmetric="true">&#x2016;</mo> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mover> <mrow> <mi>A</mi> <mi>B</mi> </mrow> <mo>&#x2192;<!-- → --></mo> </mover> </mrow> <mo>&#x2227;<!-- ∧ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mover> <mrow> <mi>A</mi> <mi>C</mi> </mrow> <mo>&#x2192;<!-- → --></mo> </mover> </mrow> </mrow> <mo symmetric="true">&#x2016;</mo> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle A={\frac {1}{2}}\left\|{{\overrightarrow {AB}}\wedge {\overrightarrow {AC}}}\right\|}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/f69a66e9141bdfa5bab76009cfae451c9afc3098" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.171ex; margin-top: -0.372ex; width:19.479ex; height:5.676ex;" alt="{\displaystyle A={\frac {1}{2}}\left\|{{\overrightarrow {AB}}\wedge {\overrightarrow {AC}}}\right\|}"></span>.</center> <p>Aplicant la <a href="/wiki/Producte_vectorial#Propietats_del_producte_vectorial" title="Producte vectorial">identitat de Lagrange</a>: </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \left\|{\overrightarrow {AB}}\wedge {\overrightarrow {AC}}\right\|^{2}+\left\|{\overrightarrow {AB}}\cdot {\overrightarrow {AC}}\right\|^{2}=\left\|{\overrightarrow {AB}}\right\|^{2}\centerdot \left\|{\overrightarrow {AC}}\right\|^{2}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msup> <mrow> <mo symmetric="true">&#x2016;</mo> <mrow> <mrow class="MJX-TeXAtom-ORD"> <mover> <mrow> <mi>A</mi> <mi>B</mi> </mrow> <mo>&#x2192;<!-- → --></mo> </mover> </mrow> <mo>&#x2227;<!-- ∧ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mover> <mrow> <mi>A</mi> <mi>C</mi> </mrow> <mo>&#x2192;<!-- → --></mo> </mover> </mrow> </mrow> <mo symmetric="true">&#x2016;</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>+</mo> <msup> <mrow> <mo symmetric="true">&#x2016;</mo> <mrow> <mrow class="MJX-TeXAtom-ORD"> <mover> <mrow> <mi>A</mi> <mi>B</mi> </mrow> <mo>&#x2192;<!-- → --></mo> </mover> </mrow> <mo>&#x22C5;<!-- ⋅ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mover> <mrow> <mi>A</mi> <mi>C</mi> </mrow> <mo>&#x2192;<!-- → --></mo> </mover> </mrow> </mrow> <mo symmetric="true">&#x2016;</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>=</mo> <msup> <mrow> <mo symmetric="true">&#x2016;</mo> <mrow class="MJX-TeXAtom-ORD"> <mover> <mrow> <mi>A</mi> <mi>B</mi> </mrow> <mo>&#x2192;<!-- → --></mo> </mover> </mrow> <mo symmetric="true">&#x2016;</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo class="MJX-variant">&#x22C5;<!-- ⋅ --></mo> <msup> <mrow> <mo symmetric="true">&#x2016;</mo> <mrow class="MJX-TeXAtom-ORD"> <mover> <mrow> <mi>A</mi> <mi>C</mi> </mrow> <mo>&#x2192;<!-- → --></mo> </mover> </mrow> <mo symmetric="true">&#x2016;</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \left\|{\overrightarrow {AB}}\wedge {\overrightarrow {AC}}\right\|^{2}+\left\|{\overrightarrow {AB}}\cdot {\overrightarrow {AC}}\right\|^{2}=\left\|{\overrightarrow {AB}}\right\|^{2}\centerdot \left\|{\overrightarrow {AC}}\right\|^{2}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/58b5306662561e2f8bc016a7c9e61ddeb2f6223b" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.171ex; width:47.43ex; height:6.009ex;" alt="{\displaystyle \left\|{\overrightarrow {AB}}\wedge {\overrightarrow {AC}}\right\|^{2}+\left\|{\overrightarrow {AB}}\cdot {\overrightarrow {AC}}\right\|^{2}=\left\|{\overrightarrow {AB}}\right\|^{2}\centerdot \left\|{\overrightarrow {AC}}\right\|^{2}}"></span></dd></dl> <p>Resulta que l'àrea del triangle també es pot expressar en funció del producte escalar dels vectors: </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle A={\frac {1}{2}}{\sqrt {\left\|{\overrightarrow {AB}}\right\|^{2}\centerdot \left\|{\overrightarrow {AC}}\right\|^{2}-\left\|{\overrightarrow {AB}}\cdot {\overrightarrow {AC}}\right\|^{2}}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>A</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </mrow> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <msup> <mrow> <mo symmetric="true">&#x2016;</mo> <mrow class="MJX-TeXAtom-ORD"> <mover> <mrow> <mi>A</mi> <mi>B</mi> </mrow> <mo>&#x2192;<!-- → --></mo> </mover> </mrow> <mo symmetric="true">&#x2016;</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo class="MJX-variant">&#x22C5;<!-- ⋅ --></mo> <msup> <mrow> <mo symmetric="true">&#x2016;</mo> <mrow class="MJX-TeXAtom-ORD"> <mover> <mrow> <mi>A</mi> <mi>C</mi> </mrow> <mo>&#x2192;<!-- → --></mo> </mover> </mrow> <mo symmetric="true">&#x2016;</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>&#x2212;<!-- − --></mo> <msup> <mrow> <mo symmetric="true">&#x2016;</mo> <mrow> <mrow class="MJX-TeXAtom-ORD"> <mover> <mrow> <mi>A</mi> <mi>B</mi> </mrow> <mo>&#x2192;<!-- → --></mo> </mover> </mrow> <mo>&#x22C5;<!-- ⋅ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mover> <mrow> <mi>A</mi> <mi>C</mi> </mrow> <mo>&#x2192;<!-- → --></mo> </mover> </mrow> </mrow> <mo symmetric="true">&#x2016;</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> </msqrt> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle A={\frac {1}{2}}{\sqrt {\left\|{\overrightarrow {AB}}\right\|^{2}\centerdot \left\|{\overrightarrow {AC}}\right\|^{2}-\left\|{\overrightarrow {AB}}\cdot {\overrightarrow {AC}}\right\|^{2}}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/e42db5adc19313ef6061451fdc11a0286835e13f" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -3.005ex; width:40.189ex; height:7.676ex;" alt="{\displaystyle A={\frac {1}{2}}{\sqrt {\left\|{\overrightarrow {AB}}\right\|^{2}\centerdot \left\|{\overrightarrow {AC}}\right\|^{2}-\left\|{\overrightarrow {AB}}\cdot {\overrightarrow {AC}}\right\|^{2}}}}"></span></dd></dl> <figure class="mw-halign-left" typeof="mw:File/Frame"><a href="/wiki/Fitxer:Triangle.TrigArea.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/6/63/Triangle.TrigArea.svg/165px-Triangle.TrigArea.svg.png" decoding="async" width="165" height="148" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/63/Triangle.TrigArea.svg/248px-Triangle.TrigArea.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/63/Triangle.TrigArea.svg/330px-Triangle.TrigArea.svg.png 2x" data-file-width="165" data-file-height="148" /></a><figcaption>Aplicant trigonometria per a calcular l'altura <i>h</i>.</figcaption></figure> <div class="mw-heading mw-heading3"><h3 id="Aplicant_trigonometria">Aplicant trigonometria</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=13" title="Modifica la secció: Aplicant trigonometria"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>L'alçada d'un triangle es pot calcular aplicant <a href="/wiki/Trigonometria" title="Trigonometria">trigonometria</a>. Fent servir la nomenclatura de la imatge de l'esquerra, l'altura és <i>h</i> = <i>a</i> sin γ. Substituit a la fórmula <i>A</i> = ½<i>bh</i>, l'àrea del triangle es pot expressar com: </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle S={\frac {1}{2}}ab\sin \gamma ={\frac {1}{2}}bc\sin \alpha ={\frac {1}{2}}ca\sin \beta .}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>S</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </mrow> <mi>a</mi> <mi>b</mi> <mi>sin</mi> <mo>&#x2061;<!-- ⁡ --></mo> <mi>&#x03B3;<!-- γ --></mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </mrow> <mi>b</mi> <mi>c</mi> <mi>sin</mi> <mo>&#x2061;<!-- ⁡ --></mo> <mi>&#x03B1;<!-- α --></mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </mrow> <mi>c</mi> <mi>a</mi> <mi>sin</mi> <mo>&#x2061;<!-- ⁡ --></mo> <mi>&#x03B2;<!-- β --></mi> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle S={\frac {1}{2}}ab\sin \gamma ={\frac {1}{2}}bc\sin \alpha ={\frac {1}{2}}ca\sin \beta .}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/99576f11356ba2700b66ccfd5dc349e4a2122168" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:38.877ex; height:5.176ex;" alt="{\displaystyle S={\frac {1}{2}}ab\sin \gamma ={\frac {1}{2}}bc\sin \alpha ={\frac {1}{2}}ca\sin \beta .}"></span></dd></dl> <p>A més, com que sin α = sin (<i>π</i> - α) = sin (β + γ), i de forma similar per als altres dos angles: </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle A={\frac {1}{2}}ab\sin(\alpha +\beta )={\frac {1}{2}}bc\sin(\beta +\gamma )={\frac {1}{2}}ca\sin(\gamma +\alpha ).}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>A</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </mrow> <mi>a</mi> <mi>b</mi> <mi>sin</mi> <mo>&#x2061;<!-- ⁡ --></mo> <mo stretchy="false">(</mo> <mi>&#x03B1;<!-- α --></mi> <mo>+</mo> <mi>&#x03B2;<!-- β --></mi> <mo stretchy="false">)</mo> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </mrow> <mi>b</mi> <mi>c</mi> <mi>sin</mi> <mo>&#x2061;<!-- ⁡ --></mo> <mo stretchy="false">(</mo> <mi>&#x03B2;<!-- β --></mi> <mo>+</mo> <mi>&#x03B3;<!-- γ --></mi> <mo stretchy="false">)</mo> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </mrow> <mi>c</mi> <mi>a</mi> <mi>sin</mi> <mo>&#x2061;<!-- ⁡ --></mo> <mo stretchy="false">(</mo> <mi>&#x03B3;<!-- γ --></mi> <mo>+</mo> <mi>&#x03B1;<!-- α --></mi> <mo stretchy="false">)</mo> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle A={\frac {1}{2}}ab\sin(\alpha +\beta )={\frac {1}{2}}bc\sin(\beta +\gamma )={\frac {1}{2}}ca\sin(\gamma +\alpha ).}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/eeec9c79fb9c2d1b84ba8b5125b4b64cb5d0bd8b" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:55.991ex; height:5.176ex;" alt="{\displaystyle A={\frac {1}{2}}ab\sin(\alpha +\beta )={\frac {1}{2}}bc\sin(\beta +\gamma )={\frac {1}{2}}ca\sin(\gamma +\alpha ).}"></span></dd></dl> <p><br style="clear:both;" /> </p> <div class="mw-heading mw-heading3"><h3 id="Fent_servir_coordenades">Fent servir coordenades</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=14" title="Modifica la secció: Fent servir coordenades"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Si el vèrtex A coincideix amb l'origen (0, 0) d'un <a href="/wiki/Sistema_de_coordenades_cartesianes" title="Sistema de coordenades cartesianes">sistema de coordenades cartesianes</a> i les coordenades dels altres dos vèrtexs venen donades per B = (<i>x</i><sub>B</sub>, <i>y</i><sub>B</sub>) i C = (<i>x</i><sub>C</sub>, <i>y</i><sub>C</sub>), llavors, com que el <a href="/wiki/Determinant_(matem%C3%A0tiques)#Determinant_de_dos_vectors_en_el_pla_euclidià" title="Determinant (matemàtiques)">determinant</a> de dos vectors és l'àrea orientada del paral·lelogram definit pels dos vectors, l'àrea <i>A</i> del triangle es pot calcular com ½ del <a href="/wiki/Valor_absolut" title="Valor absolut">valor absolut</a> del <a href="/wiki/Determinant_(matem%C3%A0tiques)" title="Determinant (matemàtiques)">determinant</a> </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle A={\frac {1}{2}}\left|\det {\begin{pmatrix}x_{B}&amp;x_{C}\\y_{B}&amp;y_{C}\end{pmatrix}}\right|={\frac {1}{2}}|x_{B}y_{C}-x_{C}y_{B}|.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>A</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </mrow> <mrow> <mo>|</mo> <mrow> <mo movablelimits="true" form="prefix">det</mo> <mrow class="MJX-TeXAtom-ORD"> <mrow> <mo>(</mo> <mtable rowspacing="4pt" columnspacing="1em"> <mtr> <mtd> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>B</mi> </mrow> </msub> </mtd> <mtd> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>C</mi> </mrow> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>B</mi> </mrow> </msub> </mtd> <mtd> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>C</mi> </mrow> </msub> </mtd> </mtr> </mtable> <mo>)</mo> </mrow> </mrow> </mrow> <mo>|</mo> </mrow> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mo stretchy="false">|</mo> </mrow> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>B</mi> </mrow> </msub> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>C</mi> </mrow> </msub> <mo>&#x2212;<!-- − --></mo> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>C</mi> </mrow> </msub> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>B</mi> </mrow> </msub> <mrow class="MJX-TeXAtom-ORD"> <mo stretchy="false">|</mo> </mrow> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle A={\frac {1}{2}}\left|\det {\begin{pmatrix}x_{B}&amp;x_{C}\\y_{B}&amp;y_{C}\end{pmatrix}}\right|={\frac {1}{2}}|x_{B}y_{C}-x_{C}y_{B}|.}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/c9a5ded5e6e5d7ad478bdf049ec2dfe71af00a03" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.505ex; width:44.991ex; height:6.176ex;" alt="{\displaystyle A={\frac {1}{2}}\left|\det {\begin{pmatrix}x_{B}&amp;x_{C}\\y_{B}&amp;y_{C}\end{pmatrix}}\right|={\frac {1}{2}}|x_{B}y_{C}-x_{C}y_{B}|.}"></span></dd></dl> <p>Pel cas general en què cap dels tres vèrtexs coincideix amb l'origen, l'equació és: </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle A={\frac {1}{2}}\left|\det {\begin{pmatrix}x_{A}&amp;x_{B}&amp;x_{C}\\y_{A}&amp;y_{B}&amp;y_{C}\\1&amp;1&amp;1\end{pmatrix}}\right|={\frac {1}{2}}{\big |}x_{A}y_{C}-x_{A}y_{B}+x_{B}y_{A}-x_{B}y_{C}+x_{C}y_{B}-x_{C}y_{A}{\big |}.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>A</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </mrow> <mrow> <mo>|</mo> <mrow> <mo movablelimits="true" form="prefix">det</mo> <mrow class="MJX-TeXAtom-ORD"> <mrow> <mo>(</mo> <mtable rowspacing="4pt" columnspacing="1em"> <mtr> <mtd> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>A</mi> </mrow> </msub> </mtd> <mtd> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>B</mi> </mrow> </msub> </mtd> <mtd> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>C</mi> </mrow> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>A</mi> </mrow> </msub> </mtd> <mtd> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>B</mi> </mrow> </msub> </mtd> <mtd> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>C</mi> </mrow> </msub> </mtd> </mtr> <mtr> <mtd> <mn>1</mn> </mtd> <mtd> <mn>1</mn> </mtd> <mtd> <mn>1</mn> </mtd> </mtr> </mtable> <mo>)</mo> </mrow> </mrow> </mrow> <mo>|</mo> </mrow> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mo maxsize="1.2em" minsize="1.2em">|</mo> </mrow> </mrow> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>A</mi> </mrow> </msub> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>C</mi> </mrow> </msub> <mo>&#x2212;<!-- − --></mo> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>A</mi> </mrow> </msub> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>B</mi> </mrow> </msub> <mo>+</mo> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>B</mi> </mrow> </msub> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>A</mi> </mrow> </msub> <mo>&#x2212;<!-- − --></mo> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>B</mi> </mrow> </msub> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>C</mi> </mrow> </msub> <mo>+</mo> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>C</mi> </mrow> </msub> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>B</mi> </mrow> </msub> <mo>&#x2212;<!-- − --></mo> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>C</mi> </mrow> </msub> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>A</mi> </mrow> </msub> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mo maxsize="1.2em" minsize="1.2em">|</mo> </mrow> </mrow> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle A={\frac {1}{2}}\left|\det {\begin{pmatrix}x_{A}&amp;x_{B}&amp;x_{C}\\y_{A}&amp;y_{B}&amp;y_{C}\\1&amp;1&amp;1\end{pmatrix}}\right|={\frac {1}{2}}{\big |}x_{A}y_{C}-x_{A}y_{B}+x_{B}y_{A}-x_{B}y_{C}+x_{C}y_{B}-x_{C}y_{A}{\big |}.}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/f597f3fec456b5f164c8133a446e3b5dc5ffbda0" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -4.171ex; width:83.771ex; height:9.509ex;" alt="{\displaystyle A={\frac {1}{2}}\left|\det {\begin{pmatrix}x_{A}&amp;x_{B}&amp;x_{C}\\y_{A}&amp;y_{B}&amp;y_{C}\\1&amp;1&amp;1\end{pmatrix}}\right|={\frac {1}{2}}{\big |}x_{A}y_{C}-x_{A}y_{B}+x_{B}y_{A}-x_{B}y_{C}+x_{C}y_{B}-x_{C}y_{A}{\big |}.}"></span></dd></dl> <p>En tres dimensions, l'àrea d'un triangle qualsevol {A = (<i>x</i><sub>A</sub>, <i>y</i><sub>A</sub>, <i>z</i><sub>A</sub>), B = (<i>x</i><sub>B</sub>, <i>y</i><sub>B</sub>, <i>z</i><sub>B</sub>) and C = (<i>x</i><sub>C</sub>, <i>y</i><sub>C</sub>, <i>z</i><sub>C</sub>)} és la <a href="/w/index.php?title=Suma_pitag%C3%B2rica&amp;action=edit&amp;redlink=1" class="new" title="Suma pitagòrica (encara no existeix)">suma pitagòrica</a> de les àrees de les respectives projeccions sobre els tres plans principals (és a dir <i>x</i> = 0, <i>y</i> = 0 i <i>z</i> = 0): </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle S={\frac {1}{2}}{\sqrt {\left(\det {\begin{pmatrix}x_{A}&amp;x_{B}&amp;x_{C}\\y_{A}&amp;y_{B}&amp;y_{C}\\1&amp;1&amp;1\end{pmatrix}}\right)^{2}+\left(\det {\begin{pmatrix}y_{A}&amp;y_{B}&amp;y_{C}\\z_{A}&amp;z_{B}&amp;z_{C}\\1&amp;1&amp;1\end{pmatrix}}\right)^{2}+\left(\det {\begin{pmatrix}z_{A}&amp;z_{B}&amp;z_{C}\\x_{A}&amp;x_{B}&amp;x_{C}\\1&amp;1&amp;1\end{pmatrix}}\right)^{2}}}.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>S</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </mrow> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <msup> <mrow> <mo>(</mo> <mrow> <mo movablelimits="true" form="prefix">det</mo> <mrow class="MJX-TeXAtom-ORD"> <mrow> <mo>(</mo> <mtable rowspacing="4pt" columnspacing="1em"> <mtr> <mtd> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>A</mi> </mrow> </msub> </mtd> <mtd> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>B</mi> </mrow> </msub> </mtd> <mtd> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>C</mi> </mrow> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>A</mi> </mrow> </msub> </mtd> <mtd> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>B</mi> </mrow> </msub> </mtd> <mtd> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>C</mi> </mrow> </msub> </mtd> </mtr> <mtr> <mtd> <mn>1</mn> </mtd> <mtd> <mn>1</mn> </mtd> <mtd> <mn>1</mn> </mtd> </mtr> </mtable> <mo>)</mo> </mrow> </mrow> </mrow> <mo>)</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>+</mo> <msup> <mrow> <mo>(</mo> <mrow> <mo movablelimits="true" form="prefix">det</mo> <mrow class="MJX-TeXAtom-ORD"> <mrow> <mo>(</mo> <mtable rowspacing="4pt" columnspacing="1em"> <mtr> <mtd> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>A</mi> </mrow> </msub> </mtd> <mtd> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>B</mi> </mrow> </msub> </mtd> <mtd> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>C</mi> </mrow> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>z</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>A</mi> </mrow> </msub> </mtd> <mtd> <msub> <mi>z</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>B</mi> </mrow> </msub> </mtd> <mtd> <msub> <mi>z</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>C</mi> </mrow> </msub> </mtd> </mtr> <mtr> <mtd> <mn>1</mn> </mtd> <mtd> <mn>1</mn> </mtd> <mtd> <mn>1</mn> </mtd> </mtr> </mtable> <mo>)</mo> </mrow> </mrow> </mrow> <mo>)</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>+</mo> <msup> <mrow> <mo>(</mo> <mrow> <mo movablelimits="true" form="prefix">det</mo> <mrow class="MJX-TeXAtom-ORD"> <mrow> <mo>(</mo> <mtable rowspacing="4pt" columnspacing="1em"> <mtr> <mtd> <msub> <mi>z</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>A</mi> </mrow> </msub> </mtd> <mtd> <msub> <mi>z</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>B</mi> </mrow> </msub> </mtd> <mtd> <msub> <mi>z</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>C</mi> </mrow> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>A</mi> </mrow> </msub> </mtd> <mtd> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>B</mi> </mrow> </msub> </mtd> <mtd> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>C</mi> </mrow> </msub> </mtd> </mtr> <mtr> <mtd> <mn>1</mn> </mtd> <mtd> <mn>1</mn> </mtd> <mtd> <mn>1</mn> </mtd> </mtr> </mtable> <mo>)</mo> </mrow> </mrow> </mrow> <mo>)</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> </msqrt> </mrow> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle S={\frac {1}{2}}{\sqrt {\left(\det {\begin{pmatrix}x_{A}&amp;x_{B}&amp;x_{C}\\y_{A}&amp;y_{B}&amp;y_{C}\\1&amp;1&amp;1\end{pmatrix}}\right)^{2}+\left(\det {\begin{pmatrix}y_{A}&amp;y_{B}&amp;y_{C}\\z_{A}&amp;z_{B}&amp;z_{C}\\1&amp;1&amp;1\end{pmatrix}}\right)^{2}+\left(\det {\begin{pmatrix}z_{A}&amp;z_{B}&amp;z_{C}\\x_{A}&amp;x_{B}&amp;x_{C}\\1&amp;1&amp;1\end{pmatrix}}\right)^{2}}}.}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/36bc7fae76befe8915a06456760485f56a836c14" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -4.171ex; width:94.654ex; height:10.509ex;" alt="{\displaystyle S={\frac {1}{2}}{\sqrt {\left(\det {\begin{pmatrix}x_{A}&amp;x_{B}&amp;x_{C}\\y_{A}&amp;y_{B}&amp;y_{C}\\1&amp;1&amp;1\end{pmatrix}}\right)^{2}+\left(\det {\begin{pmatrix}y_{A}&amp;y_{B}&amp;y_{C}\\z_{A}&amp;z_{B}&amp;z_{C}\\1&amp;1&amp;1\end{pmatrix}}\right)^{2}+\left(\det {\begin{pmatrix}z_{A}&amp;z_{B}&amp;z_{C}\\x_{A}&amp;x_{B}&amp;x_{C}\\1&amp;1&amp;1\end{pmatrix}}\right)^{2}}}.}"></span></dd></dl> <div class="mw-heading mw-heading3"><h3 id="Fent_servir_la_fórmula_d'Heró"><span id="Fent_servir_la_f.C3.B3rmula_d.27Her.C3.B3"></span>Fent servir la fórmula d'Heró</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=15" title="Modifica la secció: Fent servir la fórmula d&#039;Heró"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>La forma d'un triangle queda completament determinada per les longituds dels costats. Per tant l'àrea <i>A</i> també es pot calcular a partir només de les longituds dels costats. Hom ho aconsegueix fent servir la <a href="/wiki/F%C3%B3rmula_d%27Her%C3%B3" title="Fórmula d&#39;Heró">fórmula d'Heró</a>: </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle A={\sqrt {s(s-a)(s-b)(s-c)}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>A</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mi>s</mi> <mo stretchy="false">(</mo> <mi>s</mi> <mo>&#x2212;<!-- − --></mo> <mi>a</mi> <mo stretchy="false">)</mo> <mo stretchy="false">(</mo> <mi>s</mi> <mo>&#x2212;<!-- − --></mo> <mi>b</mi> <mo stretchy="false">)</mo> <mo stretchy="false">(</mo> <mi>s</mi> <mo>&#x2212;<!-- − --></mo> <mi>c</mi> <mo stretchy="false">)</mo> </msqrt> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle A={\sqrt {s(s-a)(s-b)(s-c)}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/f2040da62a4f48c9f502e3f38e44133524401c00" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:28.71ex; height:4.843ex;" alt="{\displaystyle A={\sqrt {s(s-a)(s-b)(s-c)}}}"></span></dd></dl> <p>on <i>s</i> = ½ (<i>a</i> + <i>b</i> + <i>c</i>) és el <b>semiperímetre</b>, és a dir la meitat del perímetre del triangle. </p><p>Una forma equivalent d'escriure la fórmula d'Heró és </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle S={\frac {1}{4}}{\sqrt {(a^{2}+b^{2}+c^{2})^{2}-2(a^{4}+b^{4}+c^{4})}}.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>S</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>4</mn> </mfrac> </mrow> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mo stretchy="false">(</mo> <msup> <mi>a</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>+</mo> <msup> <mi>b</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>+</mo> <msup> <mi>c</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>&#x2212;<!-- − --></mo> <mn>2</mn> <mo stretchy="false">(</mo> <msup> <mi>a</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>4</mn> </mrow> </msup> <mo>+</mo> <msup> <mi>b</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>4</mn> </mrow> </msup> <mo>+</mo> <msup> <mi>c</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>4</mn> </mrow> </msup> <mo stretchy="false">)</mo> </msqrt> </mrow> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle S={\frac {1}{4}}{\sqrt {(a^{2}+b^{2}+c^{2})^{2}-2(a^{4}+b^{4}+c^{4})}}.}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/0e1cfbaa6754415e1dadaac6b4431cef2b5bf577" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:42.398ex; height:5.176ex;" alt="{\displaystyle S={\frac {1}{4}}{\sqrt {(a^{2}+b^{2}+c^{2})^{2}-2(a^{4}+b^{4}+c^{4})}}.}"></span></dd></dl> <p>Aquest mètode de càlcul de l'àrea del triangle és d'una gran utilitat pràctica quan hi ha elements físics que impedeixen de poder-ne mesurar l'altura i només tenim accés a mesurar la llargada dels costats del triangle. </p> <div class="mw-heading mw-heading2"><h2 id="Propietats_dels_triangles">Propietats dels triangles</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=16" title="Modifica la secció: Propietats dels triangles"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Suma_dels_angles_d'un_triangle"><span id="Suma_dels_angles_d.27un_triangle"></span>Suma dels angles d'un triangle</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=17" title="Modifica la secció: Suma dels angles d&#039;un triangle"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/Fitxer:Demostraci%C3%B3_d%27Euclides_de_qu%C3%A8_la_suma_dels_angles_d%27un_triangle_%C3%A9s_dos_rectes.PNG" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Demostraci%C3%B3_d%27Euclides_de_qu%C3%A8_la_suma_dels_angles_d%27un_triangle_%C3%A9s_dos_rectes.PNG/220px-Demostraci%C3%B3_d%27Euclides_de_qu%C3%A8_la_suma_dels_angles_d%27un_triangle_%C3%A9s_dos_rectes.PNG" decoding="async" width="220" height="134" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/d/d6/Demostraci%C3%B3_d%27Euclides_de_qu%C3%A8_la_suma_dels_angles_d%27un_triangle_%C3%A9s_dos_rectes.PNG 1.5x" data-file-width="285" data-file-height="173" /></a><figcaption>Per demostrar que la suma dels angles d'un triangle és igual a 180 °, es perllonga la base i es traça una paral·lela al costat AB.</figcaption></figure> <p>En la Proposició 32 del Llibre I dels lements d'<a href="/wiki/Euclides" title="Euclides">Euclides</a> es demostra que la suma dels tres angles de qualsevol triangle és igual a dos rectes:<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">&#91;</span>7<span class="cite-bracket">&#93;</span></a></sup> </p> <div style="clear:&#123;&#123;#switch:left&#124;center=both&#124;#default=left;"> <table style="margin:auto; width:auto; border-collapse:collapse; border-style:none;"> <tbody><tr> <td width="20" valign="top" style="font-size:35px; padding:0 10px; text-align:left; font-family:&#39;Times New Roman&#39;, serif; font-weight:bold; color:silver;">« </td> <td valign="middle" align="left" style=""><b>Proposició 32</b>. En qualsevol triangle, si un dels costats s'allarga, aleshores l'angle exterior és igual a la suma dels angles interiors i oposats, i la suma dels tres angles del triangle és de dos angles rectes. </td> <td width="20" valign="bottom" style="font-size:35px; padding:0 10px 10px; text-align:right; font-family:&#39;Times New Roman&#39;, serif; font-weight:bold; color:silver;">» </td></tr></tbody></table></div> <p><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \alpha +\beta +\gamma =180^{\circ }=\pi ~{\mbox{radiants}}\ }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>&#x03B1;<!-- α --></mi> <mo>+</mo> <mi>&#x03B2;<!-- β --></mi> <mo>+</mo> <mi>&#x03B3;<!-- γ --></mi> <mo>=</mo> <msup> <mn>180</mn> <mrow class="MJX-TeXAtom-ORD"> <mo>&#x2218;<!-- ∘ --></mo> </mrow> </msup> <mo>=</mo> <mi>&#x03C0;<!-- π --></mi> <mtext>&#xA0;</mtext> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="false" scriptlevel="0"> <mtext>radiants</mtext> </mstyle> </mrow> <mtext>&#xA0;</mtext> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \alpha +\beta +\gamma =180^{\circ }=\pi ~{\mbox{radiants}}\ }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/51c6d3e0917045416af6134435ee29ffe9f5520f" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:31.284ex; height:2.843ex;" alt="{\displaystyle \alpha +\beta +\gamma =180^{\circ }=\pi ~{\mbox{radiants}}\ }"></span> </p><p>Euclides ho demostra traçant un triangle com el de la figura de la dreta, llavors perllonga la base i traça una paral·lela al costat AB. Aplicant els resultats de les proposicions sobre angles de rectes que es tallen. L'angle BCD és igual a l'angle ABC (β) perquè les rectes AB i CD són paral·leles i la recta BC les talla formant aquests angles alterns.<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">&#91;</span>8<span class="cite-bracket">&#93;</span></a></sup> L'angle DCE és igual a l'angle BAC (α) perquè les rectes AB i CD són paral·leles i la recta AE les talla formant aquests angles interiors. Per tant la suma d'ACB + BCD + DCE (que és igual a l'angle pla ACE, és a dir, dos angles rectes) també és igual a BAC + ABC + BCA (α + β + γ) que són els tres angles del triangle. </p> <div class="mw-heading mw-heading3"><h3 id="Longituds_dels_costats_i_desigualtat_triangular">Longituds dels costats i desigualtat triangular</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=18" title="Modifica la secció: Longituds dels costats i desigualtat triangular"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>En un triangle, la longitud d'un costat és inferior a la suma de les longituds dels altres dos costats. En altres paraules, en un triangle <i><b>ABC</b></i>, es verifiquen les tres desigualtats següents: </p> <center><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle BC&lt;BA+AC,\ AB&lt;AC+CB\ \ i\ \ AC&lt;AB+BC}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>B</mi> <mi>C</mi> <mo>&lt;</mo> <mi>B</mi> <mi>A</mi> <mo>+</mo> <mi>A</mi> <mi>C</mi> <mo>,</mo> <mtext>&#xA0;</mtext> <mi>A</mi> <mi>B</mi> <mo>&lt;</mo> <mi>A</mi> <mi>C</mi> <mo>+</mo> <mi>C</mi> <mi>B</mi> <mtext>&#xA0;</mtext> <mtext>&#xA0;</mtext> <mi>i</mi> <mtext>&#xA0;</mtext> <mtext>&#xA0;</mtext> <mi>A</mi> <mi>C</mi> <mo>&lt;</mo> <mi>A</mi> <mi>B</mi> <mo>+</mo> <mi>B</mi> <mi>C</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle BC&lt;BA+AC,\ AB&lt;AC+CB\ \ i\ \ AC&lt;AB+BC}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/033013be0fd387caf725dc87f72b5627947566de" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:54.197ex; height:2.509ex;" alt="{\displaystyle BC&lt;BA+AC,\ AB&lt;AC+CB\ \ i\ \ AC&lt;AB+BC}"></span></center> <p>Aquesta propietat és característica dels triangles. Recíprocament. Donats tres <a href="/wiki/Nombre_real" title="Nombre real">nombres reals</a> positius <b><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle a}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>a</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle a}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/ffd2487510aa438433a2579450ab2b3d557e5edc" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.23ex; height:1.676ex;" alt="{\displaystyle a}"></span></b>, <b><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle b}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>b</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle b}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/f11423fbb2e967f986e36804a8ae4271734917c3" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:0.998ex; height:2.176ex;" alt="{\displaystyle b}"></span></b> i <b><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle c}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>c</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle c}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/86a67b81c2de995bd608d5b2df50cd8cd7d92455" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.007ex; height:1.676ex;" alt="{\displaystyle c}"></span></b>, si es verifiquen les tres desigualtats&#160;: </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle a&lt;b+c,\ b&lt;a+c\ \ i\ \ c&lt;a+b}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>a</mi> <mo>&lt;</mo> <mi>b</mi> <mo>+</mo> <mi>c</mi> <mo>,</mo> <mtext>&#xA0;</mtext> <mi>b</mi> <mo>&lt;</mo> <mi>a</mi> <mo>+</mo> <mi>c</mi> <mtext>&#xA0;</mtext> <mtext>&#xA0;</mtext> <mi>i</mi> <mtext>&#xA0;</mtext> <mtext>&#xA0;</mtext> <mi>c</mi> <mo>&lt;</mo> <mi>a</mi> <mo>+</mo> <mi>b</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle a&lt;b+c,\ b&lt;a+c\ \ i\ \ c&lt;a+b}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/0b143ea112bdf05939bbc47c5c4193472c963aff" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:32.259ex; height:2.509ex;" alt="{\displaystyle a&lt;b+c,\ b&lt;a+c\ \ i\ \ c&lt;a+b}"></span></dd></dl> <p>llavors, existeix un triangle en el qual els costats fan <b><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle a}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>a</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle a}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/ffd2487510aa438433a2579450ab2b3d557e5edc" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.23ex; height:1.676ex;" alt="{\displaystyle a}"></span></b>, <b><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle b}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>b</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle b}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/f11423fbb2e967f986e36804a8ae4271734917c3" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:0.998ex; height:2.176ex;" alt="{\displaystyle b}"></span></b> i <b><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle c}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>c</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle c}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/86a67b81c2de995bd608d5b2df50cd8cd7d92455" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.007ex; height:1.676ex;" alt="{\displaystyle c}"></span></b>. </p><p>Inversament, per a verificar que existeix un triangle en el qual les longituds dels costats són <b><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle a}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>a</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle a}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/ffd2487510aa438433a2579450ab2b3d557e5edc" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.23ex; height:1.676ex;" alt="{\displaystyle a}"></span></b>, <b><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle b}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>b</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle b}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/f11423fbb2e967f986e36804a8ae4271734917c3" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:0.998ex; height:2.176ex;" alt="{\displaystyle b}"></span></b> i <b><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle c}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>c</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle c}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/86a67b81c2de995bd608d5b2df50cd8cd7d92455" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.007ex; height:1.676ex;" alt="{\displaystyle c}"></span></b>, a la pràctica, n'hi ha prou amb verificar només una de les tres desigualtats, aquella en la qual el costat més llarg és a l'esquerra de la desigualtat (així, si <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle max(a,b,c)=a}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>m</mi> <mi>a</mi> <mi>x</mi> <mo stretchy="false">(</mo> <mi>a</mi> <mo>,</mo> <mi>b</mi> <mo>,</mo> <mi>c</mi> <mo stretchy="false">)</mo> <mo>=</mo> <mi>a</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle max(a,b,c)=a}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/e873b84dce10fe5d5fea7f9d4f30132bf63803db" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:16.04ex; height:2.843ex;" alt="{\displaystyle max(a,b,c)=a}"></span> , llavors l'única desigualtat a verificar és&#160;: <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle a&lt;b+c}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>a</mi> <mo>&lt;</mo> <mi>b</mi> <mo>+</mo> <mi>c</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle a&lt;b+c}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/9f13ead6cae57cf97fab76ad2f250b6f9a8ed04b" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.505ex; width:9.173ex; height:2.343ex;" alt="{\displaystyle a&lt;b+c}"></span> ). </p><p>En cas d'igualtat, la desigualtat triangular permet de caracteritzar tres punts alineats: </p><p>M és un punt del segment [<i><b>AB</b></i>] (i per tant està alineat amb els seus extrems) si i només si&#160;: <i><b>AM + MB = AB</b></i>. </p><p>Finalment, la suma de les longituds dels tres costat d'un triangle és el seu <i>perímetre</i>. </p> <div class="mw-heading mw-heading3"><h3 id="Relacions_mètriques_en_un_triangle"><span id="Relacions_m.C3.A8triques_en_un_triangle"></span>Relacions mètriques en un triangle</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=19" title="Modifica la secció: Relacions mètriques en un triangle"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r30997230"><div role="note" class="hatnote navigation-not-searchable">Article principal: <a href="/wiki/Resoluci%C3%B3_de_triangles" title="Resolució de triangles">Resolució de triangles</a></div> <p><b>Notacions</b>&#160;: </p> <dl><dd><i>p</i> designa el semiperímetre del triangle&#160;: <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle p={\frac {1}{2}}(a+b+c)}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>p</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </mrow> <mo stretchy="false">(</mo> <mi>a</mi> <mo>+</mo> <mi>b</mi> <mo>+</mo> <mi>c</mi> <mo stretchy="false">)</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle p={\frac {1}{2}}(a+b+c)}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/bf7dd1082611f3df33b5a1b599aab74f6e4048e7" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; margin-left: -0.089ex; width:17.08ex; height:5.176ex;" alt="{\displaystyle p={\frac {1}{2}}(a+b+c)}"></span>&#160;;</dd> <dd><i>S</i> designa la superfície del triangle&#160;;</dd> <dd><i>R</i> designa el radi de la circumferència circumscrita&#160;;</dd> <dd><i>h</i> designa l'altura relativa al costat <i>BC</i> de llargada <i>a</i>&#160;;</dd> <dd><i>r</i> designa el radi de la circumferència inscrita&#160;;</dd></dl> <ul><li><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle S={\frac {ah}{2}}=pr={\frac {abc}{4R}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>S</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mi>a</mi> <mi>h</mi> </mrow> <mn>2</mn> </mfrac> </mrow> <mo>=</mo> <mi>p</mi> <mi>r</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mi>a</mi> <mi>b</mi> <mi>c</mi> </mrow> <mrow> <mn>4</mn> <mi>R</mi> </mrow> </mfrac> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle S={\frac {ah}{2}}=pr={\frac {abc}{4R}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/f4aaaaa7f0eaebe5e576551393bff48dccd7f0be" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.005ex; width:20.488ex; height:5.509ex;" alt="{\displaystyle S={\frac {ah}{2}}=pr={\frac {abc}{4R}}}"></span>&#160;;</li></ul> <p>La primera fórmula pel càlcul de la superfície és la que s'ha demostrat en la secció <a href="#Superfície">superfície</a> d'aquest mateix article. </p><p>La segona resulta de la fórmula del radi de la circumferència inscrita que s'explica a l'article <a href="/wiki/Incentre" title="Incentre">incentre</a>: <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle r={\frac {2S}{a+b+c}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>r</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mn>2</mn> <mi>S</mi> </mrow> <mrow> <mi>a</mi> <mo>+</mo> <mi>b</mi> <mo>+</mo> <mi>c</mi> </mrow> </mfrac> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle r={\frac {2S}{a+b+c}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/028b7ad51b0ed836c1b18ecf1bb636549705e2a4" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.171ex; width:13.898ex; height:5.676ex;" alt="{\displaystyle r={\frac {2S}{a+b+c}}}"></span> tenint en compte que aquí <i>p</i> representa el semi perímetre, és a dir <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle p={\frac {a+b+c}{2}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>p</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mi>a</mi> <mo>+</mo> <mi>b</mi> <mo>+</mo> <mi>c</mi> </mrow> <mn>2</mn> </mfrac> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle p={\frac {a+b+c}{2}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/0f954cd6a002e2f36009536472c1e11c36f367ee" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; margin-left: -0.089ex; width:14.108ex; height:5.343ex;" alt="{\displaystyle p={\frac {a+b+c}{2}}}"></span>. </p><p>La tercera fórmula resulta de la <a href="/wiki/Teorema_del_sinus#Demostració_del_teorema_del_sinus" title="Teorema del sinus">demostració del teorema del sinus</a> on s'obté el resultat previ de: <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle 2R={\frac {abc}{2S}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mn>2</mn> <mi>R</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mi>a</mi> <mi>b</mi> <mi>c</mi> </mrow> <mrow> <mn>2</mn> <mi>S</mi> </mrow> </mfrac> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle 2R={\frac {abc}{2S}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/63d7a647c6db69a18d572c9293ce574fbaadc141" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.005ex; width:10.095ex; height:5.509ex;" alt="{\displaystyle 2R={\frac {abc}{2S}}}"></span> d'on es dedueix la fórmula que es presenta aquí. </p> <ul><li><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle S={\frac {1}{2}}bc\,\sin {\hat {A}}={\sqrt {p(p-a)(p-b)(p-c)}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>S</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </mrow> <mi>b</mi> <mi>c</mi> <mspace width="thinmathspace" /> <mi>sin</mi> <mo>&#x2061;<!-- ⁡ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mover> <mi>A</mi> <mo stretchy="false">&#x005E;<!-- ^ --></mo> </mover> </mrow> </mrow> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mi>p</mi> <mo stretchy="false">(</mo> <mi>p</mi> <mo>&#x2212;<!-- − --></mo> <mi>a</mi> <mo stretchy="false">)</mo> <mo stretchy="false">(</mo> <mi>p</mi> <mo>&#x2212;<!-- − --></mo> <mi>b</mi> <mo stretchy="false">)</mo> <mo stretchy="false">(</mo> <mi>p</mi> <mo>&#x2212;<!-- − --></mo> <mi>c</mi> <mo stretchy="false">)</mo> </msqrt> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle S={\frac {1}{2}}bc\,\sin {\hat {A}}={\sqrt {p(p-a)(p-b)(p-c)}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/8fcb6119e6651ede2e7f411172ac7d6d7db72363" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:41.676ex; height:5.176ex;" alt="{\displaystyle S={\frac {1}{2}}bc\,\sin {\hat {A}}={\sqrt {p(p-a)(p-b)(p-c)}}}"></span> (<i><a href="/wiki/F%C3%B3rmula_d%27Her%C3%B3" title="Fórmula d&#39;Heró">Fórmula d'Heró</a></i>)&#160;;</li></ul> <p>Aquesta fórmula permet calcular la superfície directament a partir de les longituds dels costats sense haver de mesurar l'altura ni cap angle. </p> <ul><li><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle a^{2}=b^{2}+c^{2}-2bc\cos {\hat {A}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msup> <mi>a</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>=</mo> <msup> <mi>b</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>+</mo> <msup> <mi>c</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>&#x2212;<!-- − --></mo> <mn>2</mn> <mi>b</mi> <mi>c</mi> <mi>cos</mi> <mo>&#x2061;<!-- ⁡ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mover> <mi>A</mi> <mo stretchy="false">&#x005E;<!-- ^ --></mo> </mover> </mrow> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle a^{2}=b^{2}+c^{2}-2bc\cos {\hat {A}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/b121815e2cb8c2aaf30ef5fb5adde6a70d714b36" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.505ex; width:24.004ex; height:3.009ex;" alt="{\displaystyle a^{2}=b^{2}+c^{2}-2bc\cos {\hat {A}}}"></span> (<i><a href="/wiki/Teorema_del_cosinus" title="Teorema del cosinus">Teorema del cosinus</a></i>, o <i><a href="/wiki/Teorema_de_Pit%C3%A0gores" title="Teorema de Pitàgores">Teorema de Pitàgores</a> generalitzat</i>)&#160;;</li></ul> <p>El teorema del cosinus és útil per a calcular el tercer costat d'un triangle quan es coneixen dos costats i l'angle inclòs, i per a calcular els angles d'un triangle quan es coneixen els tres costats. </p> <ul><li><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\frac {a}{\sin {\hat {A}}}}={\frac {b}{\sin {\hat {B}}}}={\frac {c}{\sin {\hat {C}}}}={\frac {abc}{2S}}=2R}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mi>a</mi> <mrow> <mi>sin</mi> <mo>&#x2061;<!-- ⁡ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mover> <mi>A</mi> <mo stretchy="false">&#x005E;<!-- ^ --></mo> </mover> </mrow> </mrow> </mrow> </mfrac> </mrow> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mi>b</mi> <mrow> <mi>sin</mi> <mo>&#x2061;<!-- ⁡ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mover> <mi>B</mi> <mo stretchy="false">&#x005E;<!-- ^ --></mo> </mover> </mrow> </mrow> </mrow> </mfrac> </mrow> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mi>c</mi> <mrow> <mi>sin</mi> <mo>&#x2061;<!-- ⁡ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mover> <mi>C</mi> <mo stretchy="false">&#x005E;<!-- ^ --></mo> </mover> </mrow> </mrow> </mrow> </mfrac> </mrow> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mi>a</mi> <mi>b</mi> <mi>c</mi> </mrow> <mrow> <mn>2</mn> <mi>S</mi> </mrow> </mfrac> </mrow> <mo>=</mo> <mn>2</mn> <mi>R</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle {\frac {a}{\sin {\hat {A}}}}={\frac {b}{\sin {\hat {B}}}}={\frac {c}{\sin {\hat {C}}}}={\frac {abc}{2S}}=2R}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/0feeeaaba97235666a809ceffe8f6888853f278c" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.671ex; width:36.933ex; height:6.176ex;" alt="{\displaystyle {\frac {a}{\sin {\hat {A}}}}={\frac {b}{\sin {\hat {B}}}}={\frac {c}{\sin {\hat {C}}}}={\frac {abc}{2S}}=2R}"></span> (<i><a href="/wiki/Teorema_del_sinus" title="Teorema del sinus">Teorema del sinus</a></i>)&#160;;</li></ul> <p>Aquest teorema és útil per a calcular els altres dos costats d'un triangle quant es coneixen dos angles i un costat, un problema habitual en la tècnica de triangulació. També es pot fer servir quant es coneixen dos costats i un dels angles que no és el compres entre els dos costats; en aquest cas, la fórmula pot donar dos valors possibles per a l'angle comprés. Quan això passa, sovint només un dels resultats farà que tots els angles siguin més petits de 180 °; en altres casos, hi ha dues solucions vàlides per al triangle (vegeu <a href="/wiki/Teorema_del_sinus" title="Teorema del sinus">teorema del sinus</a> per a més informació sobre el cas ambigu). </p> <dl><dd><dl><dd>Les dues últimes fórmules més la fórmula <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\hat {A}}+{\hat {B}}+{\hat {C}}=\pi }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mover> <mi>A</mi> <mo stretchy="false">&#x005E;<!-- ^ --></mo> </mover> </mrow> </mrow> <mo>+</mo> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mover> <mi>B</mi> <mo stretchy="false">&#x005E;<!-- ^ --></mo> </mover> </mrow> </mrow> <mo>+</mo> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mover> <mi>C</mi> <mo stretchy="false">&#x005E;<!-- ^ --></mo> </mover> </mrow> </mrow> <mo>=</mo> <mi>&#x03C0;<!-- π --></mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle {\hat {A}}+{\hat {B}}+{\hat {C}}=\pi }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/27b219b3f667b0d8a9b240235b9c33309a2af8dc" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.505ex; width:15.417ex; height:3.009ex;" alt="{\displaystyle {\hat {A}}+{\hat {B}}+{\hat {C}}=\pi }"></span>, són la base dels mètodes de <a href="/wiki/Triangulaci%C3%B3" title="Triangulació">triangulació</a> en <a href="/wiki/Geod%C3%A8sia" title="Geodèsia">geodèsia</a> i en <a href="/wiki/Astronomia" title="Astronomia">astronomia</a>.</dd></dl></dd></dl> <div class="mw-heading mw-heading3"><h3 id="Triangles_semblants_i_isomètrics"><span id="Triangles_semblants_i_isom.C3.A8trics"></span>Triangles semblants i isomètrics</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=20" title="Modifica la secció: Triangles semblants i isomètrics"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Es diu que dos triangles són <b>isomètrics</b> quan els seus tres costats són respectivament iguals (iguals d'un a un). En aquest cas, existeix una <a href="/wiki/Isometria" title="Isometria">isometria</a> (per exemple una <a href="/wiki/Translaci%C3%B3_(geometria)" title="Translació (geometria)">translació</a>, una <a href="/wiki/Rotaci%C3%B3_(matem%C3%A0tiques)" title="Rotació (matemàtiques)">rotació</a> o una <a href="/wiki/Simetria" title="Simetria">simetria</a>) que transforma un en l'altre. Perquè dos triangles siguin isomètrics n'hi ha prou que es verifiqui una qualsevol de les condicions següents (llavors totes les altres també es compliran): </p> <ul><li>els tres costat són respectivament iguals dos a dos;</li> <li>dos costats tenen la mateixa longitud i un dels angles té la mateixa mesura;</li> <li>dos angles mesuren el mateix i el costat comú a tots dos angles té la mateixa longitud.</li></ul> <p>Es diu que dos triangles són <i>semblants</i> si els seus tres angles són respectivament iguals dos a dos. Llavors hi ha una relació de <a href="/wiki/Semblan%C3%A7a" title="Semblança">semblança</a> (que és la composició d'una <a href="/wiki/Simetria" title="Simetria">simetria</a> i una <a href="/wiki/Homot%C3%A8cia" title="Homotècia">homotècia</a>) que transforma l'un en l'altre. En aquest cas les longituds dels seus costats són proporcionals. </p> <div class="mw-heading mw-heading2"><h2 id="Aplicacions_dels_triangles">Aplicacions dels triangles</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=21" title="Modifica la secció: Aplicacions dels triangles"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size mw-halign-left" typeof="mw:File/Thumb"><a href="/wiki/Fitxer:Pratt_truss.PNG" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/b/b5/Pratt_truss.PNG/220px-Pratt_truss.PNG" decoding="async" width="220" height="34" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/b5/Pratt_truss.PNG/330px-Pratt_truss.PNG 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/b5/Pratt_truss.PNG/440px-Pratt_truss.PNG 2x" data-file-width="980" data-file-height="150" /></a><figcaption>Gelosia de Pratt. Dissenyada perquè les barres inclinades, que són més llargues, treballin a tracció mentre que les verticals, que són més curtes i per tant no tenen tant risc de vinclament, treballin a compressió</figcaption></figure> <p>El triangle és l'únic polígon que no permet deformar cap dels seus angles sense modificar al mateix temps la longitud d'algun dels seus costats. Aquesta propietat el fa especialment adequat per aplicacions en <a href="/wiki/Arquitectura" title="Arquitectura">arquitectura</a>. </p><p>Les <a href="/wiki/Gelosia_(estructura)" title="Gelosia (estructura)">gelosies</a> són formes <a href="/wiki/Estructura" title="Estructura">estructurals</a> formades per la interconnexió de membres rectilinis o barres. En la majoria de gelosies les barres formen triangles, això assegura que estaran sotmeses a esforços de tracció o compressió, però no a flexió. En canvi les gelosies que no estan formades per triangles es poden deformar sense allargar ni comprimir les barres i per evitar aquesta deformació els nusos i les barres han de poder resistir esforços de flexió que normalment porten a haver de donar-los dimensions més grans per tal d'assegurar que les <a href="/wiki/Tensi%C3%B3_(mec%C3%A0nica)" title="Tensió (mecànica)">tensions</a> no superen les màximes admissibles. </p> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/Fitxer:Triakistetrahedron.gif" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/5/50/Triakistetrahedron.gif/220px-Triakistetrahedron.gif" decoding="async" width="220" height="220" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/5/50/Triakistetrahedron.gif 1.5x" data-file-width="256" data-file-height="256" /></a><figcaption>El <a href="/wiki/Tetr%C3%A0edre_triakis" title="Tetràedre triakis">tetràedre triakis</a> és un <a href="/wiki/S%C3%B2lid_de_Catalan" class="mw-redirect" title="Sòlid de Catalan">sòlid de Catalan</a> que està format per 12 triangles isòsceles iguals</figcaption></figure> <div class="mw-heading mw-heading2"><h2 id="Políedres_de_cares_triangulars"><span id="Pol.C3.ADedres_de_cares_triangulars"></span>Políedres de cares triangulars</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=22" title="Modifica la secció: Políedres de cares triangulars"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Nombrosos <a href="/wiki/Pol%C3%ADedre" title="Políedre">políedres</a> tenen cares triangulars. </p><p>Hi ha tres <a href="/wiki/S%C3%B2lids_plat%C3%B2nics" class="mw-redirect" title="Sòlids platònics">sòlids platònics</a> totes les cares dels quals són triangles equilàters: el <a href="/wiki/Tetr%C3%A0edre" title="Tetràedre">tetràedre</a>, l'<a href="/wiki/Oct%C3%A0edre" title="Octàedre">octàedre</a> i l'<a href="/wiki/Icos%C3%A0edre" class="mw-redirect" title="Icosàedre">icosàedre</a>. </p><p>Tots els <a href="/wiki/S%C3%B2lids_de_Johnson" class="mw-redirect" title="Sòlids de Johnson">sòlids de Johnson</a> tenen alguna cara que és un triangle equilàter. </p><p>Hi ha 7 dels 13 <a href="/wiki/S%C3%B2lids_de_Catalan" class="mw-redirect" title="Sòlids de Catalan">sòlids de Catalan</a> totes les cares dels quals són triangles. En 5 són triangles isòsceles: el <a href="/wiki/Tetr%C3%A0edre_triakis" title="Tetràedre triakis">tetràedre triakis</a>, l'<a href="/wiki/Oct%C3%A0edre_triakis" title="Octàedre triakis">octàedre triakis</a>, el<a href="/wiki/Cub_tetrakis" title="Cub tetrakis">Cub tetrakis</a>, l'<a href="/wiki/Icos%C3%A0edre_triakis" title="Icosàedre triakis">icosàedre triakis</a>, i el <a href="/wiki/Dodec%C3%A0edre_pentakis" title="Dodecàedre pentakis">dodecàedre pentakis</a>. Els altres dos són triangles escalens: l'<a href="/wiki/Oct%C3%A0edre_hexaquis" class="mw-redirect" title="Octàedre hexaquis">octàedre hexaquis</a> i l'<a href="/wiki/Icos%C3%A0edre_hexakis" title="Icosàedre hexakis">icosàedre hexakis</a>. </p> <div class="mw-heading mw-heading2"><h2 id="Triangles_no_plans">Triangles no plans</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=23" title="Modifica la secció: Triangles no plans"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Un triangle no pla és el que no està contingut en una superfície plana. Exemples de triangles no plans en geometries no euclidianes són els triangles esfèrics en <a href="/wiki/Geometria_esf%C3%A8rica" title="Geometria esfèrica">geometria esfèrica</a> i els triangles hiperbòlics en la <a href="/wiki/Geometria_hiperb%C3%B2lica" title="Geometria hiperbòlica">geometria hiperbòlica</a>. </p><p>Mentre que en tots els triangles regulars plans la suma dels seus angles és 180 °, en els triangles corbats hi ha casos en què la suma dels angles pot ser més gran o més petita de 180 °. Els angles d'un triangle en un espai de curvatura negativa sumaran menys de 180 °, mentre que els triangles en un espai amb curvatura positiva tindran angles que sumaran més de 180 °. Per tant, si es dibuixés un triangle prou gran en la superfície de la terra, es trobaria que la suma dels seus angles seria més de 180 °. </p> <div class="mw-heading mw-heading2"><h2 id="Triangle_de_Sierpiński"><span id="Triangle_de_Sierpi.C5.84ski"></span>Triangle de Sierpiński</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=24" title="Modifica la secció: Triangle de Sierpiński"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r30997230"><div role="note" class="hatnote navigation-not-searchable">Article principal: <a href="/wiki/Triangle_de_Sierpi%C5%84ski" title="Triangle de Sierpiński">Triangle de Sierpiński</a></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/Fitxer:SierpinskiTriangle.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/8/80/SierpinskiTriangle.svg/220px-SierpinskiTriangle.svg.png" decoding="async" width="220" height="190" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/80/SierpinskiTriangle.svg/330px-SierpinskiTriangle.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/80/SierpinskiTriangle.svg/440px-SierpinskiTriangle.svg.png 2x" data-file-width="744" data-file-height="644" /></a><figcaption>Triangle de Sierpiński</figcaption></figure> <p>El triangle de Sierpiński és un objecte fractal que es construeix a partir d'un triangle. </p><p>Per construir el triangle de Sierpiński se segueix l'algoritme següent:<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">&#91;</span>9<span class="cite-bracket">&#93;</span></a></sup> </p> <ol><li>A partir d'un triangle, s'uneixen els punts mitjans dels seus costats, dividint el triangle inicial en quatre triangles</li> <li>S'elimina el triangle interior</li> <li>En cada un dels tres triangles que queden es procedeix a fer el pas 1</li></ol> <p>El triangle de Sierpiński és el límit de fer el procediment anterior de manera infinita. </p> <div class="mw-heading mw-heading2"><h2 id="Simbolisme_del_triangle">Simbolisme del triangle</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=25" title="Modifica la secció: Simbolisme del triangle"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/Fitxer:Araldiz_Manno_263.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/c/cb/Araldiz_Manno_263.png/220px-Araldiz_Manno_263.png" decoding="async" width="220" height="202" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/cb/Araldiz_Manno_263.png/330px-Araldiz_Manno_263.png 1.5x, //upload.wikimedia.org/wikipedia/commons/c/cb/Araldiz_Manno_263.png 2x" data-file-width="334" data-file-height="306" /></a><figcaption>Representació cristiana de <a href="/wiki/D%C3%A9u" title="Déu">déu</a></figcaption></figure> <p>Representa l'estabilitat i la simplicitat, perquè tota figura es pot descompondre en triangles i qualsevol cos pot sostenir-se sobre tres punts de suport ben situats. Per això es troba a la base de les construccions tradicionals (cabana, tipi...) i ha estat àmpliament adoptat pels arquitectes: és el perfil de les piràmides egípcies, però també el de les teulades, dels campanars, etc. </p><p>El triangle amb la base a sota simbolitza <a href="/wiki/D%C3%A9u" title="Déu">Déu</a> (per la doctrina de la <a href="/wiki/Sant%C3%ADssima_Trinitat" title="Santíssima Trinitat">trinitat</a> al cristianisme), en aquest cas a vegades amb un ull al mig, volent dir que Déu ho veu tot (símbol utilitzat igualment per la <a href="/wiki/Francma%C3%A7oneria" title="Francmaçoneria">francmaçoneria</a>). També era l'antic jeroglífic <a href="/wiki/Hitites" title="Hitites">hitita</a> per indicar "ciutat". Els senyals de trànsit indicant perill o atenció tenen aquesta forma, així com el símbol de la <a href="/wiki/Protecci%C3%B3_Civil" class="mw-redirect" title="Protecció Civil">Protecció Civil</a>. </p><p>Si està invertit, s'associa a la <a href="/wiki/Dona" title="Dona">dona</a>, per la forma del pubis. Durant el nazisme, els homosexuals havien de portar un <a href="/wiki/Triangle_rosa" title="Triangle rosa">triangle invertit de color rosa</a>. És també la forma del senyal de trànsit de "cediu el pas". Un triangle invertit amb una <a href="/wiki/Y" title="Y">Y</a> al centre s'anomena ull de drac. </p><p>Com a punta de sageta sigfnifica la direcció. Quan la punta mira cap a la dreta, apareix com a representació gràfica de <i>play</i> (posar en marxa) aparells musicals i informàtics. Si està duplicat, indica avançament ràpid de pista o cançó. </p><p>Dos triangles superposats al revés, com en l'<a href="/wiki/Estrella_de_David" title="Estrella de David">estrella de David</a>, simbolitzen la noció d'harmonia i d'equilibri perfecte. </p><p>El <a href="/wiki/Tetraktys" title="Tetraktys">tetraktys</a> dels pitagòrics es representa en forma de triangle. </p> <div class="mw-heading mw-heading2"><h2 id="Referències"><span id="Refer.C3.A8ncies"></span>Referències</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=26" title="Modifica la secció: Referències"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="reflist &#123;&#123;#if: &#124; references-column-count references-column-count-&#123;&#123;&#123;col&#125;&#125;&#125;" style="list-style-type: decimal;"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><a href="#cite_ref-1">↑</a></span> <span class="reference-text"><span class="citation" style="font-style:normal">«<a rel="nofollow" class="external text" href="https://dlc.iec.cat/">triangle</a>».&#32;<i>DIEC2</i>.&#32;[Consulta: 29 octubre 2018].</span></span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><a href="#cite_ref-2">↑</a></span> <span class="reference-text"><a href="#ABC">A. Buffum Chace, <i>Rhind papyrus</i></a>, pl. 73.</span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><a href="#cite_ref-3">↑</a></span> <span class="reference-text"><a href="#CM">C. Marshall, <i>Ancient Egyptian Science</i></a>, p.70</span> </li> <li id="cite_note-gamma2-4"><span class="mw-cite-backlink">↑ <sup><a href="#cite_ref-gamma2_4-0">4,0</a></sup> <sup><a href="#cite_ref-gamma2_4-1">4,1</a></sup> <sup><a href="#cite_ref-gamma2_4-2">4,2</a></sup></span> <span class="reference-text"><span class="citation book" style="font-style:normal" id="CITEREFCorbalán_Yuste2003"><span style="font-variant: small-caps;">Corbalán Yuste</span>, F. et al.. <i>Gamma 2&#160;: matemàtiques&#160;: Educació Secundària, segon curs</i>. 1a..&#32; Barcelona:&#32;Vicens Vives,&#32;2003,&#32;p.&#160;149. <span style="font-size:90%; white-space:nowrap;"><a href="/wiki/Especial:Fonts_bibliogr%C3%A0fiques/84-316-6978-2" title="Especial:Fonts bibliogràfiques/84-316-6978-2">ISBN 84-316-6978-2</a></span>.</span><span class="Z3988" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=book&amp;rft.btitle=Gamma+2+%3A+matem%C3%A0tiques+%3A+Educaci%C3%B3+Secund%C3%A0ria%2C+segon+curs&amp;rft.aulast=Corbal%C3%A1n+Yuste&amp;rft.aufirst=F.+et+al.&amp;rft.date=2003&amp;rft.edition=1a.&amp;rft.pub=Vicens+Vives&amp;rft.place=Barcelona&amp;rft.pages=149&amp;rft.isbn=84-316-6978-2"><span style="display: none;">&#160;</span></span></span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><a href="#cite_ref-5">↑</a></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://publicacions.iec.cat/repository/pdf/00000007/00000088.pdf">La geometria del triangle</a> Butlletí de la Secció de Matemàtiques de la <a href="/wiki/Societat_Catalana_de_Ci%C3%A8ncies_F%C3%ADsiques,_Qu%C3%ADmiques_i_Matem%C3%A0tiques" title="Societat Catalana de Ciències Físiques, Químiques i Matemàtiques">Societat Catalana de Ciències Físiques, Químiques i Matemàtiques</a>, Volum: 5: maig 1980, pàgina 34</span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><a href="#cite_ref-6">↑</a></span> <span class="reference-text"><span class="citació mathworld" id="Referència-Mathworld-Triangle_area"><a href="/wiki/Eric_W._Weisstein" class="mw-redirect" title="Eric W. Weisstein"><span style="font-variant:small-caps; font-variant-caps: small-caps;">Weisstein</span>, Eric W.</a>, <a rel="nofollow" class="external text" href="http://mathworld.wolfram.com/TriangleArea.html">«Triangle area»</a> a <a href="/wiki/MathWorld" title="MathWorld">MathWorld</a> (en anglès).</span></span> </li> <li id="cite_note-7"><span class="mw-cite-backlink"><a href="#cite_ref-7">↑</a></span> <span class="reference-text"><span class="citation" style="font-style:normal">«<a rel="nofollow" class="external text" href="https://web.archive.org/web/20110709052118/http://www.euclides.org/menu/elements_cat/01/proposicionsllibre1.htm#Proposici%F3%2027">Elements d'Euclides</a>». Arxivat de l'<a rel="nofollow" class="external text" href="http://www.euclides.org/menu/elements_cat/01/proposicionsllibre1.htm#Proposici%F3%2027">original</a> el 2011-07-09.&#32;[Consulta: 31 maig 2008].</span></span> </li> <li id="cite_note-8"><span class="mw-cite-backlink"><a href="#cite_ref-8">↑</a></span> <span class="reference-text">Proposició 29 dels elements d'Euclides</span> </li> <li id="cite_note-9"><span class="mw-cite-backlink"><a href="#cite_ref-9">↑</a></span> <span class="reference-text"><span class="citation" style="font-style:normal">«<a rel="nofollow" class="external text" href="https://web.archive.org/web/20121217042952/http://www.figueraspacheco.com/EPlaS/sost_ma/sierpinski.htm#2">Triangle de Sierpinski</a>». Arxivat de l'<a rel="nofollow" class="external text" href="http://www.figueraspacheco.com/EPlaS/sost_ma/sierpinski.htm#2">original</a> el 2012-12-17.&#32;[Consulta: 15 març 2009].</span></span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="Vegeu_també"><span id="Vegeu_tamb.C3.A9"></span>Vegeu també</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=27" title="Modifica la secció: Vegeu també"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Demostraci%C3%B3_de_les_identitats_trigonom%C3%A8triques" title="Demostració de les identitats trigonomètriques">Demostració de les identitats trigonomètriques</a>.</li> <li><a href="/wiki/Funcions_trigonom%C3%A8triques" class="mw-redirect" title="Funcions trigonomètriques">Funcions trigonomètriques</a>.</li> <li><a href="/wiki/Geometria_no_euclidiana" title="Geometria no euclidiana">Geometria no euclidiana</a>.</li> <li><a href="/wiki/Llista_d%27identitats_trigonom%C3%A8triques" title="Llista d&#39;identitats trigonomètriques">Llista d'identitats trigonomètriques</a>.</li> <li><a href="/wiki/Pol%C3%ADedre" title="Políedre">Políedre</a>.</li> <li><a href="/wiki/Pol%C3%ADgon" title="Polígon">Polígon</a>.</li> <li><a href="/wiki/Resoluci%C3%B3_de_triangles" title="Resolució de triangles">Resolució de triangles</a>.</li> <li><a href="/wiki/Teorema_de_Napole%C3%B3" title="Teorema de Napoleó">Teorema de Napoleó</a>.</li> <li><a href="/wiki/Trigonometria" title="Trigonometria">Trigonometria</a>.</li> <li><a href="/wiki/Trigonometria_esf%C3%A8rica" title="Trigonometria esfèrica">Trigonometria esfèrica</a>.</li></ul> <div class="mw-heading mw-heading2"><h2 id="Enllaços_externs"><span id="Enlla.C3.A7os_externs"></span>Enllaços externs</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Triangle&amp;action=edit&amp;section=28" title="Modifica la secció: Enllaços externs"><span>modifica</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a rel="nofollow" class="external text" href="http://www.euclides.org/menu/elements_cat/indexeuclides.htm">Els elements d'Euclides</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20130901142522/http://euclides.org/menu/elements_cat/indexeuclides.htm">Arxivat</a> 2013-09-01 a <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a>.</li> <li><a rel="nofollow" class="external text" href="http://www.xtec.es/~qcastell/ttw/ttwcat/portada.html">Tot triangles web</a> Una autèntica enciclopèdia de la geometria del triangle.</li></ul> <table cellpadding="2" cellspacing="0" align="right" style="margin:5px; padding: 5px; border:1px solid #aaaaaa; text-align:left;" class="infobox noprint plainlinks"> <tbody><tr> <td colspan="2" style="text-align:center; font-size:85%">En altres projectes de <a href="/wiki/Fundaci%C3%B3_Wikimedia" title="Fundació Wikimedia">Wikimedia</a>: </td></tr> <tr> <td><figure class="mw-halign-center" typeof="mw:File"><a href="/wiki/Fitxer:Commons-logo.svg" class="mw-file-description" title="Commons"><img alt="Commons" src="//upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Commons-logo.svg/17px-Commons-logo.svg.png" decoding="async" width="17" height="23" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Commons-logo.svg/26px-Commons-logo.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Commons-logo.svg/34px-Commons-logo.svg.png 2x" data-file-width="1024" data-file-height="1376" /></a><figcaption>Commons</figcaption></figure></td> <td><a href="https://commons.wikimedia.org/wiki/Category:Triangles" class="extiw" title="commons:Category:Triangles"><b>Commons</b></a> <span class="penicon"><span class="mw-valign-baseline" typeof="mw:File"><a href="https://www.wikidata.org/wiki/Q19821?uselang=ca#sitelinks-special" title="Modifica el valor a Wikidata"><img alt="Modifica el valor a Wikidata" src="//upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/10px-Arbcom_ru_editing.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/15px-Arbcom_ru_editing.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/63/Arbcom_ru_editing.svg/20px-Arbcom_ru_editing.svg.png 2x" data-file-width="600" data-file-height="600" /></a></span></span> </td></tr> </tbody></table> <div role="navigation" class="navbox" aria-labelledby="Triangle" style="padding:3px"><table class="nowraplinks collapsible collapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="3"><div class="plainlinks hlist navbar mini"><ul><li class="nv-view"><span typeof="mw:File"><a href="/wiki/Plantilla:Triangle" title="Plantilla:Triangle"><img alt="Vegeu aquesta plantilla" src="//upload.wikimedia.org/wikipedia/commons/thumb/2/28/Commons-emblem-notice.svg/18px-Commons-emblem-notice.svg.png" decoding="async" width="18" height="18" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/28/Commons-emblem-notice.svg/27px-Commons-emblem-notice.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/28/Commons-emblem-notice.svg/36px-Commons-emblem-notice.svg.png 2x" data-file-width="48" data-file-height="48" /></a></span></li></ul></div><div id="Triangle" style="font-size:114%;margin:0 4em"><a class="mw-selflink selflink">Triangle</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Tipus</th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em"><a href="/wiki/Triangle_equil%C3%A0ter" title="Triangle equilàter">Equilàter</a> <span style="font-weight:bold;">&#160;·</span>&#32; <a href="/wiki/Triangle_escal%C3%A8" title="Triangle escalè">Escalè</a> <span style="font-weight:bold;">&#160;·</span>&#32; <a href="/wiki/Triangle_is%C3%B2sceles" title="Triangle isòsceles">Isòsceles</a> <span style="font-weight:bold;">&#160;·</span>&#32; <a href="/wiki/Triangle_rectangle" title="Triangle rectangle">Rectangle</a> [<span style="font-size:90%;"><a href="/wiki/Catet" title="Catet">Catet</a> <span style="font-weight:bold;">&#160;·</span>&#32; <a href="/wiki/Hipotenusa" title="Hipotenusa">Hipotenusa</a></span>]</div></td><td class="navbox-image" rowspan="4" style="width:1px;padding:0px 0px 0px 2px"><div><span typeof="mw:File"><a href="/wiki/Fitxer:Triangulo-definicion.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/d/d1/Triangulo-definicion.png/125px-Triangulo-definicion.png" decoding="async" width="125" height="90" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/d1/Triangulo-definicion.png/188px-Triangulo-definicion.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/d1/Triangulo-definicion.png/250px-Triangulo-definicion.png 2x" data-file-width="300" data-file-height="215" /></a></span></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Centres</th><td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em"><a href="/wiki/Circumcentre" class="mw-redirect" title="Circumcentre">Circumcentre</a> <span style="font-weight:bold;">&#160;·</span>&#32; <a href="/wiki/Ortocentre" title="Ortocentre">Ortocentre</a> <span style="font-weight:bold;">&#160;·</span>&#32; <a href="/wiki/Baricentre" title="Baricentre">Baricentre</a> <span style="font-weight:bold;">&#160;·</span>&#32; <a href="/wiki/Incentre" title="Incentre">Incentre</a> <span style="font-weight:bold;">&#160;·</span>&#32; <a href="/wiki/Excentre" class="mw-redirect" title="Excentre">Excentre</a></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Rectes</th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em"><a href="/wiki/Mediatriu" title="Mediatriu">Mediatriu</a> <span style="font-weight:bold;">&#160;·</span>&#32; <a href="/wiki/Altura_(geometria)" title="Altura (geometria)">Altura</a> <span style="font-weight:bold;">&#160;·</span>&#32; <a href="/wiki/Mitjana_(geometria)" title="Mitjana (geometria)">Mitjana</a> <span style="font-weight:bold;">&#160;·</span>&#32; <a href="/wiki/Bisectriu" title="Bisectriu">Bisectriu</a> <span style="font-weight:bold;">&#160;·</span>&#32; <a href="/wiki/Recta_d%27Euler" title="Recta d&#39;Euler">Recta d'Euler</a> <span style="font-weight:bold;">&#160;·</span>&#32; <a href="/wiki/Ceviana" title="Ceviana">Ceviana</a></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Teoremes</th><td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em"><a href="/wiki/Teorema_de_l%27altura" title="Teorema de l&#39;altura">De l'altura</a> <span style="font-weight:bold;">&#160;·</span>&#32; <a href="/wiki/Teorema_de_Carnot" title="Teorema de Carnot">De Carnot</a> <span style="font-weight:bold;">&#160;·</span>&#32; <a href="/wiki/Teorema_del_catet" title="Teorema del catet">Del catet</a> <span style="font-weight:bold;">&#160;·</span>&#32; <a href="/wiki/Teorema_de_Ceva" title="Teorema de Ceva">De Ceva</a> <span style="font-weight:bold;">&#160;·</span>&#32; <a href="/wiki/Desigualtat_triangular" title="Desigualtat triangular">Desigualtat triangular</a> <span style="font-weight:bold;">&#160;·</span>&#32; <a href="/wiki/Teorema_de_l%27Huilier" title="Teorema de l&#39;Huilier">De l'Huilier</a> <span style="font-weight:bold;">&#160;·</span>&#32; <a href="/wiki/Teorema_de_Menelau" title="Teorema de Menelau">De Menelau</a> <span style="font-weight:bold;">&#160;·</span>&#32; <a href="/wiki/Teorema_de_Pit%C3%A0gores" title="Teorema de Pitàgores">De Pitàgores</a> <span style="font-weight:bold;">&#160;·</span>&#32; <a href="/wiki/Teorema_de_Stewart" title="Teorema de Stewart">De Stewart</a> <span style="font-weight:bold;">&#160;·</span>&#32; <a href="/wiki/Teorema_de_Viviani" title="Teorema de Viviani">De Viviani</a></div></td></tr></tbody></table></div> <p><span style="display: none;" class="interProject"><a href="https://ca.wiktionary.org/wiki/Triangle" class="extiw" title="wikt:Triangle">Viccionari</a></span> </p> <div role="navigation" class="navbox" aria-labelledby="Polígons" style="padding:3px"><table class="nowraplinks collapsible collapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><div class="plainlinks hlist navbar mini"><ul><li class="nv-view"><span typeof="mw:File"><a href="/wiki/Plantilla:Pol%C3%ADgons" title="Plantilla:Polígons"><img alt="Vegeu aquesta plantilla" src="//upload.wikimedia.org/wikipedia/commons/thumb/2/28/Commons-emblem-notice.svg/18px-Commons-emblem-notice.svg.png" decoding="async" width="18" height="18" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/28/Commons-emblem-notice.svg/27px-Commons-emblem-notice.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/28/Commons-emblem-notice.svg/36px-Commons-emblem-notice.svg.png 2x" data-file-width="48" data-file-height="48" /></a></span></li></ul></div><div id="Polígons" style="font-size:114%;margin:0 4em"><a href="/wiki/Pol%C3%ADgon" title="Polígon">Polígons</a></div></th></tr><tr><td class="navbox-abovebelow" colspan="2"><div id="RegularLlista"><style data-mw-deduplicate="TemplateStyles:r31792667">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul dl,.mw-parser-output .hlist ul ol,.mw-parser-output .hlist ul ul{display:inline}.mw-parser-output .hlist .mw-empty-li{display:none}.mw-parser-output .hlist dt::after{content:": "}.mw-parser-output .hlist dd::after,.mw-parser-output .hlist li::after{content:" · ";font-weight:bold}.mw-parser-output .hlist dd:last-child::after,.mw-parser-output .hlist dt:last-child::after,.mw-parser-output .hlist li:last-child::after{content:none}.mw-parser-output .hlist dd dd:first-child::before,.mw-parser-output .hlist dd dt:first-child::before,.mw-parser-output .hlist dd li:first-child::before,.mw-parser-output .hlist dt dd:first-child::before,.mw-parser-output .hlist dt dt:first-child::before,.mw-parser-output .hlist dt li:first-child::before,.mw-parser-output .hlist li dd:first-child::before,.mw-parser-output .hlist li dt:first-child::before,.mw-parser-output .hlist li li:first-child::before{content:" (";font-weight:normal}.mw-parser-output .hlist dd dd:last-child::after,.mw-parser-output .hlist dd dt:last-child::after,.mw-parser-output .hlist dd li:last-child::after,.mw-parser-output .hlist dt dd:last-child::after,.mw-parser-output .hlist dt dt:last-child::after,.mw-parser-output .hlist dt li:last-child::after,.mw-parser-output .hlist li dd:last-child::after,.mw-parser-output .hlist li dt:last-child::after,.mw-parser-output .hlist li li:last-child::after{content:")";font-weight:normal}.mw-parser-output .hlist ol{counter-reset:listitem}.mw-parser-output .hlist ol>li{counter-increment:listitem}.mw-parser-output .hlist ol>li::before{content:" "counter(listitem)"\a0 "}.mw-parser-output .hlist dd ol>li:first-child::before,.mw-parser-output .hlist dt ol>li:first-child::before,.mw-parser-output .hlist li ol>li:first-child::before{content:" ("counter(listitem)"\a0 "}</style><div class="hlist"><ul><li><a href="/wiki/Pol%C3%ADgon_regular" class="mw-redirect" title="Polígon regular">Regular</a></li><li><a href="/w/index.php?title=Llista_de_pol%C3%ADgons&amp;action=edit&amp;redlink=1" class="new" title="Llista de polígons (encara no existeix)">Llista</a></li></ul></div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">1–10 costats</th><td class="navbox-list navbox-odd hlist" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em"> <ul><li><a href="/w/index.php?title=Mon%C3%B2gon&amp;action=edit&amp;redlink=1" class="new" title="Monògon (encara no existeix)">Monògon</a></li> <li><a href="/w/index.php?title=D%C3%ADgon&amp;action=edit&amp;redlink=1" class="new" title="Dígon (encara no existeix)">Dígon</a></li> <li><a class="mw-selflink selflink">Triangle</a> <ul><li><a href="/wiki/Triangle_equil%C3%A0ter" title="Triangle equilàter">Equilàter</a></li> <li><a href="/wiki/Triangle_is%C3%B2sceles" title="Triangle isòsceles">Isòsceles</a></li></ul></li> <li><a href="/wiki/Quadril%C3%A0ter" title="Quadrilàter">Quadrilàter</a> <ul><li><a href="/wiki/Quadrat_(geometria)" class="mw-redirect" title="Quadrat (geometria)">Quadrat</a></li> <li><a href="/wiki/Rectangle" title="Rectangle">Rectangle</a></li> <li><a href="/wiki/Rombe" title="Rombe">Rombe</a></li> <li><a href="/wiki/Paral%C2%B7lelogram" title="Paral·lelogram">Paral·lelogram</a></li> <li><a href="/wiki/Trapezi" title="Trapezi">Trapezi</a></li> <li><a href="/wiki/Deltoide" title="Deltoide">Deltoide</a></li></ul></li> <li><a href="/wiki/Pent%C3%A0gon_(geometria)" title="Pentàgon (geometria)">Pentàgon</a></li> <li><a href="/wiki/Hex%C3%A0gon" title="Hexàgon">Hexàgon</a></li> <li><a href="/wiki/Hept%C3%A0gon" title="Heptàgon">Heptàgon</a></li> <li><a href="/wiki/Oct%C3%A0gon" title="Octàgon">Octàgon</a></li> <li><a href="/wiki/Enne%C3%A0gon" title="Enneàgon">Enneàgon</a></li> <li><a href="/wiki/Dec%C3%A0gon" title="Decàgon">Decàgon</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">11–20 costats</th><td class="navbox-list navbox-even hlist" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em"> <ul><li><a href="/wiki/Hendec%C3%A0gon" title="Hendecàgon">Hendecàgon</a></li> <li><a href="/wiki/Dodec%C3%A0gon" title="Dodecàgon">Dodecàgon</a></li> <li><a href="/wiki/Tridec%C3%A0gon" title="Tridecàgon">Tridecàgon</a></li> <li><a href="/w/index.php?title=Tetradec%C3%A0gon&amp;action=edit&amp;redlink=1" class="new" title="Tetradecàgon (encara no existeix)">Tetradecàgon</a></li> <li><a href="/wiki/Pentadec%C3%A0gon" title="Pentadecàgon">Pentadecàgon</a></li> <li><a href="/wiki/Hexadec%C3%A0gon" title="Hexadecàgon">Hexadecàgon</a></li> <li><a href="/wiki/Heptadec%C3%A0gon" title="Heptadecàgon">Heptadecàgon</a></li> <li><a href="/wiki/Octodec%C3%A0gon" title="Octodecàgon">Octodecàgon</a></li> <li><a href="/w/index.php?title=Enneadec%C3%A0gon&amp;action=edit&amp;redlink=1" class="new" title="Enneadecàgon (encara no existeix)">Enneadecàgon</a></li> <li><a href="/wiki/Icos%C3%A0gon" title="Icosàgon">Icosàgon</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">21–100 costats<br />(seleccionats)</th><td class="navbox-list navbox-odd hlist" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em"> <ul><li><a href="/w/index.php?title=Icos%C3%ADdigon&amp;action=edit&amp;redlink=1" class="new" title="Icosídigon (encara no existeix)">Icosídigon (22)</a></li> <li><a href="/w/index.php?title=Icositetr%C3%A0gon&amp;action=edit&amp;redlink=1" class="new" title="Icositetràgon (encara no existeix)">Icositetràgon (24)</a></li> <li><a href="/w/index.php?title=Icosihex%C3%A0gon&amp;action=edit&amp;redlink=1" class="new" title="Icosihexàgon (encara no existeix)">Icosihexàgon (26)</a></li> <li><a href="/w/index.php?title=Icosioct%C3%A0gon&amp;action=edit&amp;redlink=1" class="new" title="Icosioctàgon (encara no existeix)">Icosioctàgon (28)</a></li> <li><a href="/w/index.php?title=Triacont%C3%A0gon&amp;action=edit&amp;redlink=1" class="new" title="Triacontàgon (encara no existeix)">Triacontàgon (30)</a></li> <li><a href="/w/index.php?title=Triacontad%C3%ADgon&amp;action=edit&amp;redlink=1" class="new" title="Triacontadígon (encara no existeix)">Triacontadígon (32)</a></li> <li><a href="/w/index.php?title=Triacontatetr%C3%A0gon&amp;action=edit&amp;redlink=1" class="new" title="Triacontatetràgon (encara no existeix)">Triacontatetràgon (34)</a></li> <li><a href="/w/index.php?title=Tetracont%C3%A0gon&amp;action=edit&amp;redlink=1" class="new" title="Tetracontàgon (encara no existeix)">Tetracontàgon (40)</a></li> <li><a href="/w/index.php?title=Tetracontad%C3%ADgon&amp;action=edit&amp;redlink=1" class="new" title="Tetracontadígon (encara no existeix)">Tetracontadígon (42)</a></li> <li><a href="/w/index.php?title=Tetracontaoct%C3%A0gon&amp;action=edit&amp;redlink=1" class="new" title="Tetracontaoctàgon (encara no existeix)">Tetracontaoctàgon (48)</a></li> <li><a href="/w/index.php?title=Pentacont%C3%A0gon&amp;action=edit&amp;redlink=1" class="new" title="Pentacontàgon (encara no existeix)">Pentacontàgon (50)</a></li> <li><a href="/w/index.php?title=Hexacont%C3%A0gon&amp;action=edit&amp;redlink=1" class="new" title="Hexacontàgon (encara no existeix)">Hexacontàgon (60)</a></li> <li><a href="/w/index.php?title=Hexacontatetr%C3%A0gon&amp;action=edit&amp;redlink=1" class="new" title="Hexacontatetràgon (encara no existeix)">Hexacontatetràgon (64)</a></li> <li><a href="/w/index.php?title=Heptacont%C3%A0gon&amp;action=edit&amp;redlink=1" class="new" title="Heptacontàgon (encara no existeix)">Heptacontàgon (70)</a></li> <li><a href="/w/index.php?title=Octacont%C3%A0gon&amp;action=edit&amp;redlink=1" class="new" title="Octacontàgon (encara no existeix)">Octacontàgon (80)</a></li> <li><a href="/w/index.php?title=Enneacont%C3%A0gon&amp;action=edit&amp;redlink=1" class="new" title="Enneacontàgon (encara no existeix)">Enneacontàgon (90)</a></li> <li><a href="/w/index.php?title=Enneacontahex%C3%A0gon&amp;action=edit&amp;redlink=1" class="new" title="Enneacontahexàgon (encara no existeix)">Enneacontahexàgon (96)</a></li> <li><a href="/w/index.php?title=Hect%C3%B2gon&amp;action=edit&amp;redlink=1" class="new" title="Hectògon (encara no existeix)">Hectògon (100)</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">&gt;100 costats</th><td class="navbox-list navbox-even hlist" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em"> <ul><li><a href="/w/index.php?title=120-gon&amp;action=edit&amp;redlink=1" class="new" title="120-gon (encara no existeix)">120-gon</a></li> <li><a href="/w/index.php?title=257-gon&amp;action=edit&amp;redlink=1" class="new" title="257-gon (encara no existeix)">257-gon</a></li> <li><a href="/w/index.php?title=360-gon&amp;action=edit&amp;redlink=1" class="new" title="360-gon (encara no existeix)">360-gon</a></li> <li><a href="/w/index.php?title=Xili%C3%A0gon&amp;action=edit&amp;redlink=1" class="new" title="Xiliàgon (encara no existeix)">Xiliàgon (1,000)</a></li> <li><a href="/w/index.php?title=Miri%C3%A0gon&amp;action=edit&amp;redlink=1" class="new" title="Miriàgon (encara no existeix)">Miriàgon (10,000)</a></li> <li><a href="/w/index.php?title=65537-gon&amp;action=edit&amp;redlink=1" class="new" title="65537-gon (encara no existeix)">65537-gon</a></li> <li><a href="/w/index.php?title=Meg%C3%A0gon&amp;action=edit&amp;redlink=1" class="new" title="Megàgon (encara no existeix)">Megàgon (1,000,000)</a></li> <li><a href="/w/index.php?title=Apeir%C3%B2gon&amp;action=edit&amp;redlink=1" class="new" title="Apeirògon (encara no existeix)">Apeirògon (∞)</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Pol%C3%ADgon_estelat" title="Polígon estelat">Polígons estelats</a><br />(5–12 costats)</th><td class="navbox-list navbox-odd hlist" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em"> <ul><li><a href="/wiki/Pentacle" title="Pentacle">Pentagrama</a></li> <li><a href="/wiki/Hexagrama" title="Hexagrama">Hexagrama</a></li> <li><a href="/w/index.php?title=Heptagrama&amp;action=edit&amp;redlink=1" class="new" title="Heptagrama (encara no existeix)">Heptagrama</a></li> <li><a href="/wiki/Octagrama" title="Octagrama">Octagrama</a></li> <li><a href="/wiki/Enneagrama_(geometria)" title="Enneagrama (geometria)">Enneagrama</a></li> <li><a href="/w/index.php?title=Decagrama&amp;action=edit&amp;redlink=1" class="new" title="Decagrama (encara no existeix)">Decagrama</a></li> <li><a href="/w/index.php?title=Hendecagrama&amp;action=edit&amp;redlink=1" class="new" title="Hendecagrama (encara no existeix)">Hendecagrama</a></li> <li><a href="/w/index.php?title=Dodecagrama&amp;action=edit&amp;redlink=1" class="new" title="Dodecagrama (encara no existeix)">Dodecagrama</a></li></ul> </div></td></tr></tbody></table></div> <div role="navigation" class="navbox" aria-label="Navbox" style="padding:3px"><table class="nowraplinks hlist navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="row" 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