CINXE.COM

<!DOCTYPE html> <html class="client-nojs vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-toc-available" lang="ja" dir="ltr"> <head> <meta charset="UTF-8"> <title>半径 - Wikipedia</title> <script>(function(){var className="client-js vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-toc-available";var cookie=document.cookie.match(/(?:^|; )jawikimwclientpreferences=([^;]+)/);if(cookie){cookie[1].split('%2C').forEach(function(pref){className=className.replace(new RegExp('(^| )'+pref.replace(/-clientpref-\w+$|[^\w-]+/g,'')+'-clientpref-\\w+( |$)'),'$1'+pref+'$2');});}document.documentElement.className=className;}());RLCONF={"wgBreakFrames":false,"wgSeparatorTransformTable":["",""],"wgDigitTransformTable":["",""],"wgDefaultDateFormat":"ja", "wgMonthNames":["","1月","2月","3月","4月","5月","6月","7月","8月","9月","10月","11月","12月"],"wgRequestId":"4ca33d4d-0068-4081-b4ed-2d26c0249401","wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"半径","wgTitle":"半径","wgCurRevisionId":92717028,"wgRevisionId":92717028,"wgArticleId":27648,"wgIsArticle":true,"wgIsRedirect":false,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":["GND識別子が指定されている記事","J9U識別子が指定されている記事","LCCN識別子が指定されている記事","幾何学","初等数学","長さ","数学に関する記事"],"wgPageViewLanguage":"ja","wgPageContentLanguage":"ja","wgPageContentModel":"wikitext","wgRelevantPageName":"半径","wgRelevantArticleId":27648,"wgIsProbablyEditable":true,"wgRelevantPageIsProbablyEditable":true,"wgRestrictionEdit":[],"wgRestrictionMove":[],"wgNoticeProject":"wikipedia","wgCiteReferencePreviewsActive":true, "wgMediaViewerOnClick":true,"wgMediaViewerEnabledByDefault":true,"wgPopupsFlags":0,"wgVisualEditor":{"pageLanguageCode":"ja","pageLanguageDir":"ltr","pageVariantFallbacks":"ja"},"wgMFDisplayWikibaseDescriptions":{"search":true,"watchlist":true,"tagline":true,"nearby":true},"wgWMESchemaEditAttemptStepOversample":false,"wgWMEPageLength":10000,"wgRelatedArticlesCompat":[],"wgCentralAuthMobileDomain":false,"wgEditSubmitButtonLabelPublish":true,"wgULSPosition":"interlanguage","wgULSisCompactLinksEnabled":false,"wgVector2022LanguageInHeader":true,"wgULSisLanguageSelectorEmpty":false,"wgWikibaseItemId":"Q173817","wgCheckUserClientHintsHeadersJsApi":["brands","architecture","bitness","fullVersionList","mobile","model","platform","platformVersion"],"GEHomepageSuggestedEditsEnableTopics":true,"wgGETopicsMatchModeEnabled":false,"wgGEStructuredTaskRejectionReasonTextInputEnabled":false,"wgGELevelingUpEnabledForUser":false};RLSTATE={"ext.gadget.PDFLinkIcon":"ready","ext.gadget.RedirectColor": "ready","ext.globalCssJs.user.styles":"ready","site.styles":"ready","user.styles":"ready","ext.globalCssJs.user":"ready","user":"ready","user.options":"loading","ext.cite.styles":"ready","ext.math.styles":"ready","skins.vector.search.codex.styles":"ready","skins.vector.styles":"ready","skins.vector.icons":"ready","ext.wikimediamessages.styles":"ready","ext.visualEditor.desktopArticleTarget.noscript":"ready","ext.uls.interlanguage":"ready","wikibase.client.init":"ready","ext.wikimediaBadges":"ready"};RLPAGEMODULES=["ext.cite.ux-enhancements","mediawiki.page.media","site","mediawiki.page.ready","mediawiki.toc","skins.vector.js","ext.centralNotice.geoIP","ext.centralNotice.startUp","ext.gadget.NormalizeCharWidth","ext.gadget.suppressEnterAtSummaryBox","ext.gadget.checkSignature","ext.gadget.charinsert","ext.gadget.WikiMiniAtlas","ext.gadget.switcher","ext.gadget.protectionIndicator","ext.urlShortener.toolbar","ext.centralauth.centralautologin","mmv.bootstrap","ext.popups", "ext.visualEditor.desktopArticleTarget.init","ext.visualEditor.targetLoader","ext.echo.centralauth","ext.eventLogging","ext.wikimediaEvents","ext.navigationTiming","ext.uls.interface","ext.cx.eventlogging.campaigns","ext.cx.uls.quick.actions","wikibase.client.vector-2022","ext.checkUser.clientHints","ext.growthExperiments.SuggestedEditSession","wikibase.sidebar.tracking"];</script> <script>(RLQ=window.RLQ||[]).push(function(){mw.loader.impl(function(){return["user.options@12s5i",function($,jQuery,require,module){mw.user.tokens.set({"patrolToken":"+\\","watchToken":"+\\","csrfToken":"+\\"}); }];});});</script> <link rel="stylesheet" href="/w/load.php?lang=ja&modules=ext.cite.styles%7Cext.math.styles%7Cext.uls.interlanguage%7Cext.visualEditor.desktopArticleTarget.noscript%7Cext.wikimediaBadges%7Cext.wikimediamessages.styles%7Cskins.vector.icons%2Cstyles%7Cskins.vector.search.codex.styles%7Cwikibase.client.init&only=styles&skin=vector-2022"> <script async="" src="/w/load.php?lang=ja&modules=startup&only=scripts&raw=1&skin=vector-2022"></script> <meta name="ResourceLoaderDynamicStyles" content=""> <link rel="stylesheet" href="/w/load.php?lang=ja&modules=ext.gadget.PDFLinkIcon%2CRedirectColor&only=styles&skin=vector-2022"> <link rel="stylesheet" href="/w/load.php?lang=ja&modules=site.styles&only=styles&skin=vector-2022"> <meta name="generator" content="MediaWiki 1.44.0-wmf.4"> <meta name="referrer" content="origin"> <meta name="referrer" content="origin-when-cross-origin"> <meta name="robots" content="max-image-preview:standard"> <meta name="format-detection" content="telephone=no"> <meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/c/c3/%E7%90%83%E3%81%AE%E5%8D%8A%E5%BE%84.png"> <meta property="og:image:width" content="1200"> <meta property="og:image:height" content="1200"> <meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/c/c3/%E7%90%83%E3%81%AE%E5%8D%8A%E5%BE%84.png"> <meta property="og:image:width" content="800"> <meta property="og:image:height" content="800"> <meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/thumb/c/c3/%E7%90%83%E3%81%AE%E5%8D%8A%E5%BE%84.png/640px-%E7%90%83%E3%81%AE%E5%8D%8A%E5%BE%84.png"> <meta property="og:image:width" content="640"> <meta property="og:image:height" content="640"> <meta name="viewport" content="width=1120"> <meta property="og:title" content="半径 - Wikipedia"> <meta property="og:type" content="website"> <link rel="preconnect" href="//upload.wikimedia.org"> <link rel="alternate" media="only screen and (max-width: 640px)" href="//ja.m.wikipedia.org/wiki/%E5%8D%8A%E5%BE%84"> <link rel="alternate" type="application/x-wiki" title="編集" href="/w/index.php?title=%E5%8D%8A%E5%BE%84&action=edit"> <link rel="apple-touch-icon" href="/static/apple-touch/wikipedia.png"> <link rel="icon" href="/static/favicon/wikipedia.ico"> <link rel="search" type="application/opensearchdescription+xml" href="/w/rest.php/v1/search" title="Wikipedia (ja)"> <link rel="EditURI" type="application/rsd+xml" href="//ja.wikipedia.org/w/api.php?action=rsd"> <link rel="canonical" href="https://ja.wikipedia.org/wiki/%E5%8D%8A%E5%BE%84"> <link rel="license" href="https://creativecommons.org/licenses/by-sa/4.0/deed.ja"> <link rel="alternate" type="application/atom+xml" title="WikipediaのAtomフィード" href="/w/index.php?title=%E7%89%B9%E5%88%A5:%E6%9C%80%E8%BF%91%E3%81%AE%E6%9B%B4%E6%96%B0&feed=atom"> <link rel="dns-prefetch" href="//meta.wikimedia.org" /> <link rel="dns-prefetch" href="//login.wikimedia.org"> </head> <body class="skin--responsive skin-vector skin-vector-search-vue mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject mw-editable page-半径 rootpage-半径 skin-vector-2022 action-view"><a class="mw-jump-link" href="#bodyContent">コンテンツにスキップ</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="サイト"> <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="メインメニュー" > <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">メインメニュー</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">メインメニュー</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-main-menu.pin">サイドバーに移動</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-main-menu.unpin">非表示</button> </div> <div id="p-navigation" class="vector-menu mw-portlet mw-portlet-navigation" > <div class="vector-menu-heading"> 案内 </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-mainpage-description" class="mw-list-item"><a href="/wiki/%E3%83%A1%E3%82%A4%E3%83%B3%E3%83%9A%E3%83%BC%E3%82%B8" title="メインページに移動する [z]" accesskey="z"><span>メインページ</span></a></li><li id="n-portal" class="mw-list-item"><a href="/wiki/Wikipedia:%E3%82%B3%E3%83%9F%E3%83%A5%E3%83%8B%E3%83%86%E3%82%A3%E3%83%BB%E3%83%9D%E3%83%BC%E3%82%BF%E3%83%AB" title="このプロジェクトについて、できること、情報を入手する場所"><span>コミュニティ・ポータル</span></a></li><li id="n-currentevents" class="mw-list-item"><a href="/wiki/Portal:%E6%9C%80%E8%BF%91%E3%81%AE%E5%87%BA%E6%9D%A5%E4%BA%8B" title="最近の出来事の背景を知る"><span>最近の出来事</span></a></li><li id="n-newpages" class="mw-list-item"><a href="/wiki/%E7%89%B9%E5%88%A5:%E6%96%B0%E3%81%97%E3%81%84%E3%83%9A%E3%83%BC%E3%82%B8" title="最近新規に作成されたページの一覧"><span>新しいページ</span></a></li><li id="n-recentchanges" class="mw-list-item"><a href="/wiki/%E7%89%B9%E5%88%A5:%E6%9C%80%E8%BF%91%E3%81%AE%E6%9B%B4%E6%96%B0" title="このウィキにおける最近の更新の一覧 [r]" accesskey="r"><span>最近の更新</span></a></li><li id="n-randompage" class="mw-list-item"><a href="/wiki/%E7%89%B9%E5%88%A5:%E3%81%8A%E3%81%BE%E3%81%8B%E3%81%9B%E8%A1%A8%E7%A4%BA" title="無作為に選択されたページを読み込む [x]" accesskey="x"><span>おまかせ表示</span></a></li><li id="n-sandbox" class="mw-list-item"><a href="/wiki/Wikipedia:%E3%82%B5%E3%83%B3%E3%83%89%E3%83%9C%E3%83%83%E3%82%AF%E3%82%B9" title="練習用のページ"><span>練習用ページ</span></a></li><li id="n-commonsupload" class="mw-list-item"><a href="//commons.wikimedia.org/wiki/Special:UploadWizard?uselang=ja" title="画像やメディアファイルをウィキメディア・コモンズにアップロード"><span>アップロード (ウィキメディア・コモンズ)</span></a></li> </ul> </div> </div> <div id="p-help" class="vector-menu mw-portlet mw-portlet-help" > <div class="vector-menu-heading"> ヘルプ </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-help" class="mw-list-item"><a href="/wiki/Help:%E7%9B%AE%E6%AC%A1" title="情報を得る場所"><span>ヘルプ</span></a></li><li id="n-villagepump" class="mw-list-item"><a href="/wiki/Wikipedia:%E4%BA%95%E6%88%B8%E7%AB%AF" title="プロジェクトについての意見交換"><span>井戸端</span></a></li><li id="n-notice" class="mw-list-item"><a href="/wiki/Wikipedia:%E3%81%8A%E7%9F%A5%E3%82%89%E3%81%9B" title="プロジェクトについてのお知らせ"><span>お知らせ</span></a></li><li id="n-bugreportspage" class="mw-list-item"><a href="/wiki/Wikipedia:%E3%83%90%E3%82%B0%E3%81%AE%E5%A0%B1%E5%91%8A" title="ウィキペディア・ソフトウェアのバグ報告"><span>バグの報告</span></a></li><li id="n-contact" class="mw-list-item"><a href="/wiki/Wikipedia:%E9%80%A3%E7%B5%A1%E5%85%88" title="ウィキペディアやウィキメディア財団に関する連絡先"><span>ウィキペディアに関するお問い合わせ</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> <a href="/wiki/%E3%83%A1%E3%82%A4%E3%83%B3%E3%83%9A%E3%83%BC%E3%82%B8" 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="Wikipedia" src="/static/images/mobile/copyright/wikipedia-wordmark-ja.svg" style="width: 7.5em; height: 1.25em;"> <img class="mw-logo-tagline" alt="" src="/static/images/mobile/copyright/wikipedia-tagline-ja.svg" width="100" height="14" style="width: 6.25em; 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/%E7%89%B9%E5%88%A5:%E6%A4%9C%E7%B4%A2" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only search-toggle" title="Wikipedia内を検索 [f]" accesskey="f"><span class="vector-icon mw-ui-icon-search mw-ui-icon-wikimedia-search"></span> <span>検索</span> </a> <div class="vector-typeahead-search-container"> <div class="cdx-typeahead-search cdx-typeahead-search--show-thumbnail cdx-typeahead-search--auto-expand-width"> <form action="/w/index.php" id="searchform" class="cdx-search-input cdx-search-input--has-end-button"> <div id="simpleSearch" class="cdx-search-input__input-wrapper" data-search-loc="header-moved"> <div class="cdx-text-input cdx-text-input--has-start-icon"> <input class="cdx-text-input__input" type="search" name="search" placeholder="Wikipedia内を検索" aria-label="Wikipedia内を検索" autocapitalize="sentences" title="Wikipedia内を検索 [f]" accesskey="f" id="searchInput" > <span class="cdx-text-input__icon cdx-text-input__start-icon"></span> </div> <input type="hidden" name="title" value="特別:検索"> </div> <button class="cdx-button cdx-search-input__end-button">検索</button> </form> </div> </div> </div> <nav class="vector-user-links vector-user-links-wide" aria-label="個人用ツール"> <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="表示"> <div id="vector-appearance-dropdown" class="vector-dropdown " title="ページのフォントサイズ、幅、色の外観を変更する" > <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="表示" > <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">表示</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&utm_medium=sidebar&utm_campaign=C13_ja.wikipedia.org&uselang=ja" class=""><span>寄付</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=%E7%89%B9%E5%88%A5:%E3%82%A2%E3%82%AB%E3%82%A6%E3%83%B3%E3%83%88%E4%BD%9C%E6%88%90&returnto=%E5%8D%8A%E5%BE%84" title="アカウントを作成してログインすることをお勧めしますが、必須ではありません" class=""><span>アカウント作成</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=%E7%89%B9%E5%88%A5:%E3%83%AD%E3%82%B0%E3%82%A4%E3%83%B3&returnto=%E5%8D%8A%E5%BE%84" title="ログインすることを推奨します。ただし、必須ではありません。 [o]" accesskey="o" class=""><span>ログイン</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="その他の操作" > <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="個人用ツール" > <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">個人用ツール</span> </label> <div class="vector-dropdown-content"> <div id="p-personal" class="vector-menu mw-portlet mw-portlet-personal user-links-collapsible-item" title="利用者メニュー" > <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&utm_medium=sidebar&utm_campaign=C13_ja.wikipedia.org&uselang=ja"><span>寄付</span></a></li><li id="pt-createaccount" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=%E7%89%B9%E5%88%A5:%E3%82%A2%E3%82%AB%E3%82%A6%E3%83%B3%E3%83%88%E4%BD%9C%E6%88%90&returnto=%E5%8D%8A%E5%BE%84" title="アカウントを作成してログインすることをお勧めしますが、必須ではありません"><span class="vector-icon mw-ui-icon-userAdd mw-ui-icon-wikimedia-userAdd"></span> <span>アカウント作成</span></a></li><li id="pt-login" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=%E7%89%B9%E5%88%A5:%E3%83%AD%E3%82%B0%E3%82%A4%E3%83%B3&returnto=%E5%8D%8A%E5%BE%84" title="ログインすることを推奨します。ただし、必須ではありません。 [o]" accesskey="o"><span class="vector-icon mw-ui-icon-logIn mw-ui-icon-wikimedia-logIn"></span> <span>ログイン</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"> ログアウトした編集者のページ <a href="/wiki/Wikipedia:%E3%82%A6%E3%82%A3%E3%82%AD%E3%83%9A%E3%83%87%E3%82%A3%E3%82%A2%E3%81%B8%E3%82%88%E3%81%86%E3%81%93%E3%81%9D" aria-label="編集の詳細"><span>もっと詳しく</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/%E7%89%B9%E5%88%A5:%E8%87%AA%E5%88%86%E3%81%AE%E6%8A%95%E7%A8%BF%E8%A8%98%E9%8C%B2" title="このIPアドレスからなされた編集の一覧 [y]" accesskey="y"><span>投稿記録</span></a></li><li id="pt-anontalk" class="mw-list-item"><a href="/wiki/%E7%89%B9%E5%88%A5:%E3%83%88%E3%83%BC%E3%82%AF%E3%83%9A%E3%83%BC%E3%82%B8" title="このIPアドレスからなされた編集についての議論 [n]" accesskey="n"><span>トーク</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"></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="サイト"> <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="目次" 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">目次</h2> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-toc.pin">サイドバーに移動</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">非表示</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">ページ先頭</div> </a> </li> <li id="toc-概要" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#概要"> <div class="vector-toc-text"> <span class="vector-toc-numb">1</span> <span>概要</span> </div> </a> <ul id="toc-概要-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-半径公式" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#半径公式"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>半径公式</span> </div> </a> <button aria-controls="toc-半径公式-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>半径公式サブセクションを切り替えます</span> </button> <ul id="toc-半径公式-sublist" class="vector-toc-list"> <li id="toc-円" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#円"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1</span> <span>円</span> </div> </a> <ul id="toc-円-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-正多角形" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#正多角形"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2</span> <span>正多角形</span> </div> </a> <ul id="toc-正多角形-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-超立方体" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#超立方体"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.3</span> <span>超立方体</span> </div> </a> <ul id="toc-超立方体-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-座標系の動径" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#座標系の動径"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>座標系の動径</span> </div> </a> <button aria-controls="toc-座標系の動径-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>座標系の動径サブセクションを切り替えます</span> </button> <ul id="toc-座標系の動径-sublist" class="vector-toc-list"> <li id="toc-極座標系" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#極座標系"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1</span> <span>極座標系</span> </div> </a> <ul id="toc-極座標系-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-円筒座標系" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#円筒座標系"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.2</span> <span>円筒座標系</span> </div> </a> <ul id="toc-円筒座標系-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-球面座標系" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#球面座標系"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.3</span> <span>球面座標系</span> </div> </a> <ul id="toc-球面座標系-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-脚注" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#脚注"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>脚注</span> </div> </a> <button aria-controls="toc-脚注-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>脚注サブセクションを切り替えます</span> </button> <ul id="toc-脚注-sublist" class="vector-toc-list"> <li id="toc-注釈" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#注釈"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.1</span> <span>注釈</span> </div> </a> <ul id="toc-注釈-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-出典" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#出典"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.2</span> <span>出典</span> </div> </a> <ul id="toc-出典-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-関連項目" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#関連項目"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>関連項目</span> </div> </a> <ul id="toc-関連項目-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-外部リンク" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#外部リンク"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>外部リンク</span> </div> </a> <ul id="toc-外部リンク-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="目次" 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="目次の表示・非表示を切り替え" > <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">目次の表示・非表示を切り替え</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">半径</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="特定の記事の別の言語版に移動します。利用可能な言語102件" > <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-102" 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">102の言語版</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-af mw-list-item"><a href="https://af.wikipedia.org/wiki/Radius" title="アフリカーンス語: Radius" lang="af" hreflang="af" data-title="Radius" data-language-autonym="Afrikaans" data-language-local-name="アフリカーンス語" 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/Radius_(Kreis)" title="スイスドイツ語: Radius (Kreis)" lang="gsw" hreflang="gsw" data-title="Radius (Kreis)" data-language-autonym="Alemannisch" data-language-local-name="スイスドイツ語" 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%AC%E1%8B%B5%E1%8B%A8%E1%88%B5" title="アムハラ語: ሬድየስ" lang="am" hreflang="am" data-title="ሬድየስ" data-language-autonym="አማርኛ" data-language-local-name="アムハラ語" 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/Radio_(cheometr%C3%ADa)" title="アラゴン語: Radio (cheometría)" lang="an" hreflang="an" data-title="Radio (cheometría)" data-language-autonym="Aragonés" data-language-local-name="アラゴン語" class="interlanguage-link-target"><span>Aragonés</span></a></li><li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D9%86%D8%B5%D9%81_%D8%A7%D9%84%D9%82%D8%B7%D8%B1" title="アラビア語: نصف القطر" lang="ar" hreflang="ar" data-title="نصف القطر" data-language-autonym="العربية" data-language-local-name="アラビア語" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-ast mw-list-item"><a href="https://ast.wikipedia.org/wiki/Radiu_(xeometr%C3%ADa)" title="アストゥリアス語: Radiu (xeometría)" lang="ast" hreflang="ast" data-title="Radiu (xeometría)" data-language-autonym="Asturianu" data-language-local-name="アストゥリアス語" class="interlanguage-link-target"><span>Asturianu</span></a></li><li class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikipedia.org/wiki/Radius" title="アゼルバイジャン語: Radius" lang="az" hreflang="az" data-title="Radius" data-language-autonym="Azərbaycanca" data-language-local-name="アゼルバイジャン語" class="interlanguage-link-target"><span>Azərbaycanca</span></a></li><li class="interlanguage-link interwiki-ba mw-list-item"><a href="https://ba.wikipedia.org/wiki/%D0%A0%D0%B0%D0%B4%D0%B8%D1%83%D1%81" title="バシキール語: Радиус" lang="ba" hreflang="ba" data-title="Радиус" data-language-autonym="Башҡортса" data-language-local-name="バシキール語" class="interlanguage-link-target"><span>Башҡортса</span></a></li><li class="interlanguage-link interwiki-be mw-list-item"><a href="https://be.wikipedia.org/wiki/%D0%A0%D0%B0%D0%B4%D1%8B%D1%83%D1%81" title="ベラルーシ語: Радыус" lang="be" hreflang="be" data-title="Радыус" data-language-autonym="Беларуская" data-language-local-name="ベラルーシ語" 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%A0%D0%B0%D0%B4%D1%8B%D1%8E%D1%81" title="Belarusian (Taraškievica orthography): Радыюс" lang="be-tarask" hreflang="be-tarask" data-title="Радыюс" 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%A0%D0%B0%D0%B4%D0%B8%D1%83%D1%81" title="ブルガリア語: Радиус" lang="bg" hreflang="bg" data-title="Радиус" data-language-autonym="Български" data-language-local-name="ブルガリア語" class="interlanguage-link-target"><span>Български</span></a></li><li class="interlanguage-link interwiki-bn mw-list-item"><a href="https://bn.wikipedia.org/wiki/%E0%A6%AC%E0%A7%8D%E0%A6%AF%E0%A6%BE%E0%A6%B8%E0%A6%BE%E0%A6%B0%E0%A7%8D%E0%A6%A7" title="ベンガル語: ব্যাসার্ধ" lang="bn" hreflang="bn" data-title="ব্যাসার্ধ" data-language-autonym="বাংলা" data-language-local-name="ベンガル語" class="interlanguage-link-target"><span>বাংলা</span></a></li><li class="interlanguage-link interwiki-br mw-list-item"><a href="https://br.wikipedia.org/wiki/Skin_(geometriezh)" title="ブルトン語: Skin (geometriezh)" lang="br" hreflang="br" data-title="Skin (geometriezh)" data-language-autonym="Brezhoneg" data-language-local-name="ブルトン語" 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/Polupre%C4%8Dnik" title="ボスニア語: Poluprečnik" lang="bs" hreflang="bs" data-title="Poluprečnik" data-language-autonym="Bosanski" data-language-local-name="ボスニア語" class="interlanguage-link-target"><span>Bosanski</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Radi_(geometria)" title="カタロニア語: Radi (geometria)" lang="ca" hreflang="ca" data-title="Radi (geometria)" data-language-autonym="Català" data-language-local-name="カタロニア語" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-ckb mw-list-item"><a href="https://ckb.wikipedia.org/wiki/%D9%86%DB%8C%D9%88%DB%95%D8%AA%DB%8C%D8%B1%DB%95" title="中央クルド語: نیوەتیرە" lang="ckb" hreflang="ckb" data-title="نیوەتیرە" data-language-autonym="کوردی" data-language-local-name="中央クルド語" class="interlanguage-link-target"><span>کوردی</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Polom%C4%9Br" title="チェコ語: Poloměr" lang="cs" hreflang="cs" data-title="Poloměr" data-language-autonym="Čeština" data-language-local-name="チェコ語" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-cv mw-list-item"><a href="https://cv.wikipedia.org/wiki/%D0%A0%D0%B0%D0%B4%D0%B8%D1%83%D1%81" title="チュヴァシ語: Радиус" lang="cv" hreflang="cv" data-title="Радиус" data-language-autonym="Чӑвашла" data-language-local-name="チュヴァシ語" 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/Radiws" title="ウェールズ語: Radiws" lang="cy" hreflang="cy" data-title="Radiws" data-language-autonym="Cymraeg" data-language-local-name="ウェールズ語" 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/Radius" title="デンマーク語: Radius" lang="da" hreflang="da" data-title="Radius" data-language-autonym="Dansk" data-language-local-name="デンマーク語" 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/Radius" title="ドイツ語: Radius" lang="de" hreflang="de" data-title="Radius" data-language-autonym="Deutsch" data-language-local-name="ドイツ語" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/%CE%91%CE%BA%CF%84%CE%AF%CE%BD%CE%B1_(%CE%B3%CE%B5%CF%89%CE%BC%CE%B5%CF%84%CF%81%CE%AF%CE%B1)" title="ギリシャ語: Ακτίνα (γεωμετρία)" lang="el" hreflang="el" data-title="Ακτίνα (γεωμετρία)" data-language-autonym="Ελληνικά" data-language-local-name="ギリシャ語" class="interlanguage-link-target"><span>Ελληνικά</span></a></li><li class="interlanguage-link interwiki-eml mw-list-item"><a href="https://eml.wikipedia.org/wiki/R%C3%A2%C7%B5_(giumetr%C3%ACa)" title="エミリア・ロマーニャ語: Râǵ (giumetrìa)" lang="egl" hreflang="egl" data-title="Râǵ (giumetrìa)" data-language-autonym="Emiliàn e rumagnòl" data-language-local-name="エミリア・ロマーニャ語" class="interlanguage-link-target"><span>Emiliàn e rumagnòl</span></a></li><li class="interlanguage-link interwiki-en mw-list-item"><a href="https://en.wikipedia.org/wiki/Radius" title="英語: Radius" lang="en" hreflang="en" data-title="Radius" data-language-autonym="English" data-language-local-name="英語" 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/Radiuso" title="エスペラント語: Radiuso" lang="eo" hreflang="eo" data-title="Radiuso" data-language-autonym="Esperanto" data-language-local-name="エスペラント語" 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/Radio_(geometr%C3%ADa)" title="スペイン語: Radio (geometría)" lang="es" hreflang="es" data-title="Radio (geometría)" data-language-autonym="Español" data-language-local-name="スペイン語" 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/Raadius" title="エストニア語: Raadius" lang="et" hreflang="et" data-title="Raadius" data-language-autonym="Eesti" data-language-local-name="エストニア語" 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/Erradio_(geometria)" title="バスク語: Erradio (geometria)" lang="eu" hreflang="eu" data-title="Erradio (geometria)" data-language-autonym="Euskara" data-language-local-name="バスク語" 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/%D8%B4%D8%B9%D8%A7%D8%B9" title="ペルシア語: شعاع" lang="fa" hreflang="fa" data-title="شعاع" data-language-autonym="فارسی" data-language-local-name="ペルシア語" 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/S%C3%A4de_(geometria)" title="フィンランド語: Säde (geometria)" lang="fi" hreflang="fi" data-title="Säde (geometria)" data-language-autonym="Suomi" data-language-local-name="フィンランド語" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Rayon_(g%C3%A9om%C3%A9trie)" title="フランス語: Rayon (géométrie)" lang="fr" hreflang="fr" data-title="Rayon (géométrie)" data-language-autonym="Français" data-language-local-name="フランス語" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-frr badge-Q70894304 mw-list-item" title=""><a href="https://frr.wikipedia.org/wiki/Raadius" title="北フリジア語: Raadius" lang="frr" hreflang="frr" data-title="Raadius" data-language-autonym="Nordfriisk" data-language-local-name="北フリジア語" class="interlanguage-link-target"><span>Nordfriisk</span></a></li><li class="interlanguage-link interwiki-gd mw-list-item"><a href="https://gd.wikipedia.org/wiki/Reidius" title="スコットランド・ゲール語: Reidius" lang="gd" hreflang="gd" data-title="Reidius" data-language-autonym="Gàidhlig" data-language-local-name="スコットランド・ゲール語" class="interlanguage-link-target"><span>Gàidhlig</span></a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/Raio_(xeometr%C3%ADa)" title="ガリシア語: Raio (xeometría)" lang="gl" hreflang="gl" data-title="Raio (xeometría)" data-language-autonym="Galego" data-language-local-name="ガリシア語" 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%9C%E0%AB%8D%E0%AA%AF%E0%AA%BE" title="グジャラート語: ત્રિજ્યા" lang="gu" hreflang="gu" data-title="ત્રિજ્યા" data-language-autonym="ગુજરાતી" data-language-local-name="グジャラート語" class="interlanguage-link-target"><span>ગુજરાતી</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%A8%D7%93%D7%99%D7%95%D7%A1" title="ヘブライ語: רדיוס" lang="he" hreflang="he" data-title="רדיוס" data-language-autonym="עברית" data-language-local-name="ヘブライ語" 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%9C%E0%A5%8D%E0%A4%AF%E0%A4%BE" title="ヒンディー語: त्रिज्या" lang="hi" hreflang="hi" data-title="त्रिज्या" data-language-autonym="हिन्दी" data-language-local-name="ヒンディー語" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-hy mw-list-item"><a href="https://hy.wikipedia.org/wiki/%D5%87%D5%A1%D5%BC%D5%A1%D5%BE%D5%AB%D5%B2" title="アルメニア語: Շառավիղ" lang="hy" hreflang="hy" data-title="Շառավիղ" data-language-autonym="Հայերեն" data-language-local-name="アルメニア語" 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/Radio_(geometria)" title="インターリングア: Radio (geometria)" lang="ia" hreflang="ia" data-title="Radio (geometria)" data-language-autonym="Interlingua" data-language-local-name="インターリングア" 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/Jari-jari" title="インドネシア語: Jari-jari" lang="id" hreflang="id" data-title="Jari-jari" data-language-autonym="Bahasa Indonesia" data-language-local-name="インドネシア語" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-inh mw-list-item"><a href="https://inh.wikipedia.org/wiki/%D0%93%D3%80%D0%B0%D0%B9%D0%B8%D1%81%D1%82" title="イングーシ語: ГӀайист" lang="inh" hreflang="inh" data-title="ГӀайист" data-language-autonym="ГӀалгӀай" data-language-local-name="イングーシ語" class="interlanguage-link-target"><span>ГӀалгӀай</span></a></li><li class="interlanguage-link interwiki-is mw-list-item"><a href="https://is.wikipedia.org/wiki/Geisli_(r%C3%BAmfr%C3%A6%C3%B0i)" title="アイスランド語: Geisli (rúmfræði)" lang="is" hreflang="is" data-title="Geisli (rúmfræði)" data-language-autonym="Íslenska" data-language-local-name="アイスランド語" 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/Raggio_(geometria)" title="イタリア語: Raggio (geometria)" lang="it" hreflang="it" data-title="Raggio (geometria)" data-language-autonym="Italiano" data-language-local-name="イタリア語" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-ka mw-list-item"><a href="https://ka.wikipedia.org/wiki/%E1%83%A0%E1%83%90%E1%83%93%E1%83%98%E1%83%A3%E1%83%A1%E1%83%98" title="ジョージア語: რადიუსი" lang="ka" hreflang="ka" data-title="რადიუსი" data-language-autonym="ქართული" data-language-local-name="ジョージア語" class="interlanguage-link-target"><span>ქართული</span></a></li><li class="interlanguage-link interwiki-kab mw-list-item"><a href="https://kab.wikipedia.org/wiki/Aqqa%E1%B9%9B" title="カビル語: Aqqaṛ" lang="kab" hreflang="kab" data-title="Aqqaṛ" data-language-autonym="Taqbaylit" data-language-local-name="カビル語" class="interlanguage-link-target"><span>Taqbaylit</span></a></li><li class="interlanguage-link interwiki-kk mw-list-item"><a href="https://kk.wikipedia.org/wiki/%D0%A0%D0%B0%D0%B4%D0%B8%D1%83%D1%81" title="カザフ語: Радиус" lang="kk" hreflang="kk" data-title="Радиус" data-language-autonym="Қазақша" data-language-local-name="カザフ語" class="interlanguage-link-target"><span>Қазақша</span></a></li><li class="interlanguage-link interwiki-km mw-list-item"><a href="https://km.wikipedia.org/wiki/%E1%9E%80%E1%9E%B6%E1%9F%86" title="クメール語: កាំ" lang="km" hreflang="km" data-title="កាំ" data-language-autonym="ភាសាខ្មែរ" data-language-local-name="クメール語" class="interlanguage-link-target"><span>ភាសាខ្មែរ</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EB%B0%98%EC%A7%80%EB%A6%84" title="韓国語: 반지름" lang="ko" hreflang="ko" data-title="반지름" data-language-autonym="한국어" data-language-local-name="韓国語" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-ky mw-list-item"><a href="https://ky.wikipedia.org/wiki/%D0%A0%D0%B0%D0%B4%D0%B8%D1%83%D1%81_(%D0%B0%D0%B9%D0%BB%D0%B0%D0%BD%D0%B0%D0%BD%D1%8B%D0%BD)" title="キルギス語: Радиус (айлананын)" lang="ky" hreflang="ky" data-title="Радиус (айлананын)" data-language-autonym="Кыргызча" data-language-local-name="キルギス語" class="interlanguage-link-target"><span>Кыргызча</span></a></li><li class="interlanguage-link interwiki-lb mw-list-item"><a href="https://lb.wikipedia.org/wiki/Radius" title="ルクセンブルク語: Radius" lang="lb" hreflang="lb" data-title="Radius" data-language-autonym="Lëtzebuergesch" data-language-local-name="ルクセンブルク語" class="interlanguage-link-target"><span>Lëtzebuergesch</span></a></li><li class="interlanguage-link interwiki-lt mw-list-item"><a href="https://lt.wikipedia.org/wiki/Apskritimo_spindulys" title="リトアニア語: Apskritimo spindulys" lang="lt" hreflang="lt" data-title="Apskritimo spindulys" data-language-autonym="Lietuvių" data-language-local-name="リトアニア語" 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/R%C4%81diuss" title="ラトビア語: Rādiuss" lang="lv" hreflang="lv" data-title="Rādiuss" data-language-autonym="Latviešu" data-language-local-name="ラトビア語" 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/Tana_(je%C3%B4metria)" title="マダガスカル語: Tana (jeômetria)" lang="mg" hreflang="mg" data-title="Tana (jeômetria)" data-language-autonym="Malagasy" data-language-local-name="マダガスカル語" class="interlanguage-link-target"><span>Malagasy</span></a></li><li class="interlanguage-link interwiki-mk mw-list-item"><a href="https://mk.wikipedia.org/wiki/%D0%9F%D0%BE%D0%BB%D1%83%D0%BF%D1%80%D0%B5%D1%87%D0%BD%D0%B8%D0%BA" title="マケドニア語: Полупречник" lang="mk" hreflang="mk" data-title="Полупречник" data-language-autonym="Македонски" data-language-local-name="マケドニア語" 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%86%E0%B4%B0%E0%B4%82" title="マラヤーラム語: ആരം" lang="ml" hreflang="ml" data-title="ആരം" data-language-autonym="മലയാളം" data-language-local-name="マラヤーラム語" class="interlanguage-link-target"><span>മലയാളം</span></a></li><li class="interlanguage-link interwiki-mn mw-list-item"><a href="https://mn.wikipedia.org/wiki/%D0%A0%D0%B0%D0%B4%D0%B8%D1%83%D1%81" title="モンゴル語: Радиус" lang="mn" hreflang="mn" data-title="Радиус" data-language-autonym="Монгол" data-language-local-name="モンゴル語" 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%9C%E0%A5%8D%E0%A4%AF%E0%A4%BE" title="マラーティー語: त्रिज्या" lang="mr" hreflang="mr" data-title="त्रिज्या" data-language-autonym="मराठी" data-language-local-name="マラーティー語" 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/Jejari" title="マレー語: Jejari" lang="ms" hreflang="ms" data-title="Jejari" data-language-autonym="Bahasa Melayu" data-language-local-name="マレー語" class="interlanguage-link-target"><span>Bahasa Melayu</span></a></li><li class="interlanguage-link interwiki-my mw-list-item"><a href="https://my.wikipedia.org/wiki/%E1%80%A1%E1%80%81%E1%80%BB%E1%80%84%E1%80%BA%E1%80%B8%E1%80%9D%E1%80%80%E1%80%BA" title="ミャンマー語: အချင်းဝက်" lang="my" hreflang="my" data-title="အချင်းဝက်" data-language-autonym="မြန်မာဘာသာ" data-language-local-name="ミャンマー語" 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%85%E0%A4%B0%E0%A5%8D%E0%A4%A7%E0%A4%B5%E0%A5%8D%E0%A4%AF%E0%A4%BE%E0%A4%B8" title="ネパール語: अर्धव्यास" lang="ne" hreflang="ne" data-title="अर्धव्यास" data-language-autonym="नेपाली" data-language-local-name="ネパール語" class="interlanguage-link-target"><span>नेपाली</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Straal_(wiskunde)" title="オランダ語: Straal (wiskunde)" lang="nl" hreflang="nl" data-title="Straal (wiskunde)" data-language-autonym="Nederlands" data-language-local-name="オランダ語" 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/Radius" title="ノルウェー語(ニーノシュク): Radius" lang="nn" hreflang="nn" data-title="Radius" data-language-autonym="Norsk nynorsk" data-language-local-name="ノルウェー語(ニーノシュク)" 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/Radius" title="ノルウェー語(ブークモール): Radius" lang="nb" hreflang="nb" data-title="Radius" data-language-autonym="Norsk bokmål" data-language-local-name="ノルウェー語(ブークモール)" class="interlanguage-link-target"><span>Norsk bokmål</span></a></li><li class="interlanguage-link interwiki-oc mw-list-item"><a href="https://oc.wikipedia.org/wiki/Rai_(geometria)" title="オック語: Rai (geometria)" lang="oc" hreflang="oc" data-title="Rai (geometria)" data-language-autonym="Occitan" data-language-local-name="オック語" class="interlanguage-link-target"><span>Occitan</span></a></li><li class="interlanguage-link interwiki-om mw-list-item"><a href="https://om.wikipedia.org/wiki/Raadiyesii" title="オロモ語: Raadiyesii" lang="om" hreflang="om" data-title="Raadiyesii" data-language-autonym="Oromoo" data-language-local-name="オロモ語" class="interlanguage-link-target"><span>Oromoo</span></a></li><li class="interlanguage-link interwiki-pa mw-list-item"><a href="https://pa.wikipedia.org/wiki/%E0%A8%B0%E0%A9%87%E0%A8%A1%E0%A9%80%E0%A8%85%E0%A8%B8" title="パンジャブ語: ਰੇਡੀਅਸ" lang="pa" hreflang="pa" data-title="ਰੇਡੀਅਸ" data-language-autonym="ਪੰਜਾਬੀ" data-language-local-name="パンジャブ語" class="interlanguage-link-target"><span>ਪੰਜਾਬੀ</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Promie%C5%84_(geometria)" title="ポーランド語: Promień (geometria)" lang="pl" hreflang="pl" data-title="Promień (geometria)" data-language-autonym="Polski" data-language-local-name="ポーランド語" 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%B1%D8%AF%D8%A7%D8%B3" title="Western Punjabi: رداس" lang="pnb" hreflang="pnb" data-title="رداس" data-language-autonym="پنجابی" data-language-local-name="Western Punjabi" class="interlanguage-link-target"><span>پنجابی</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Raio_(geometria)" title="ポルトガル語: Raio (geometria)" lang="pt" hreflang="pt" data-title="Raio (geometria)" data-language-autonym="Português" data-language-local-name="ポルトガル語" 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/Illwa" title="ケチュア語: Illwa" lang="qu" hreflang="qu" data-title="Illwa" data-language-autonym="Runa Simi" data-language-local-name="ケチュア語" 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/Raz%C4%83" title="ルーマニア語: Rază" lang="ro" hreflang="ro" data-title="Rază" data-language-autonym="Română" data-language-local-name="ルーマニア語" 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%A0%D0%B0%D0%B4%D0%B8%D1%83%D1%81" title="ロシア語: Радиус" lang="ru" hreflang="ru" data-title="Радиус" data-language-autonym="Русский" data-language-local-name="ロシア語" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-sc mw-list-item"><a href="https://sc.wikipedia.org/wiki/Raju_(geometria)" title="サルデーニャ語: Raju (geometria)" lang="sc" hreflang="sc" data-title="Raju (geometria)" data-language-autonym="Sardu" data-language-local-name="サルデーニャ語" class="interlanguage-link-target"><span>Sardu</span></a></li><li class="interlanguage-link interwiki-sco mw-list-item"><a href="https://sco.wikipedia.org/wiki/Radius" title="スコットランド語: Radius" lang="sco" hreflang="sco" data-title="Radius" data-language-autonym="Scots" data-language-local-name="スコットランド語" class="interlanguage-link-target"><span>Scots</span></a></li><li class="interlanguage-link interwiki-sh mw-list-item"><a href="https://sh.wikipedia.org/wiki/Radijus" title="セルボ・クロアチア語: Radijus" lang="sh" hreflang="sh" data-title="Radijus" data-language-autonym="Srpskohrvatski / српскохрватски" data-language-local-name="セルボ・クロアチア語" 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%85%E0%B6%BB%E0%B6%BA" title="シンハラ語: අරය" lang="si" hreflang="si" data-title="අරය" data-language-autonym="සිංහල" data-language-local-name="シンハラ語" 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/Radius" title="シンプル英語: Radius" lang="en-simple" hreflang="en-simple" data-title="Radius" data-language-autonym="Simple English" data-language-local-name="シンプル英語" 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/Polomer_(kru%C5%BEnica)" title="スロバキア語: Polomer (kružnica)" lang="sk" hreflang="sk" data-title="Polomer (kružnica)" data-language-autonym="Slovenčina" data-language-local-name="スロバキア語" 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/Polmer" title="スロベニア語: Polmer" lang="sl" hreflang="sl" data-title="Polmer" data-language-autonym="Slovenščina" data-language-local-name="スロベニア語" class="interlanguage-link-target"><span>Slovenščina</span></a></li><li class="interlanguage-link interwiki-sn mw-list-item"><a href="https://sn.wikipedia.org/wiki/Taramunyongo" title="ショナ語: Taramunyongo" lang="sn" hreflang="sn" data-title="Taramunyongo" data-language-autonym="ChiShona" data-language-local-name="ショナ語" 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/Gacan_(Joomitiri)" title="ソマリ語: Gacan (Joomitiri)" lang="so" hreflang="so" data-title="Gacan (Joomitiri)" data-language-autonym="Soomaaliga" data-language-local-name="ソマリ語" 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/Rrezja" title="アルバニア語: Rrezja" lang="sq" hreflang="sq" data-title="Rrezja" data-language-autonym="Shqip" data-language-local-name="アルバニア語" 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%9F%D0%BE%D0%BB%D1%83%D0%BF%D1%80%D0%B5%D1%87%D0%BD%D0%B8%D0%BA" title="セルビア語: Полупречник" lang="sr" hreflang="sr" data-title="Полупречник" data-language-autonym="Српски / srpski" data-language-local-name="セルビア語" class="interlanguage-link-target"><span>Српски / srpski</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Radie" title="スウェーデン語: Radie" lang="sv" hreflang="sv" data-title="Radie" data-language-autonym="Svenska" data-language-local-name="スウェーデン語" 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/Nusukipenyo" title="スワヒリ語: Nusukipenyo" lang="sw" hreflang="sw" data-title="Nusukipenyo" data-language-autonym="Kiswahili" data-language-local-name="スワヒリ語" 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/Pr%C5%8Dmiy%C5%84_(geometryj%C5%8F)" title="シレジア語: Prōmiyń (geometryjŏ)" lang="szl" hreflang="szl" data-title="Prōmiyń (geometryjŏ)" data-language-autonym="Ślůnski" data-language-local-name="シレジア語" 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%86%E0%AE%B0%E0%AE%AE%E0%AF%8D,_%E0%AE%B5%E0%AE%9F%E0%AE%BF%E0%AE%B5%E0%AE%BF%E0%AE%AF%E0%AE%B2%E0%AF%8D" title="タミル語: ஆரம், வடிவியல்" lang="ta" hreflang="ta" data-title="ஆரம், வடிவியல்" data-language-autonym="தமிழ்" data-language-local-name="タミル語" 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%B5%E0%B1%8D%E0%B0%AF%E0%B0%BE%E0%B0%B8%E0%B0%BE%E0%B0%B0%E0%B1%8D%E0%B0%A5%E0%B0%AE%E0%B1%81" title="テルグ語: వ్యాసార్థము" lang="te" hreflang="te" data-title="వ్యాసార్థము" data-language-autonym="తెలుగు" data-language-local-name="テルグ語" class="interlanguage-link-target"><span>తెలుగు</span></a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikipedia.org/wiki/%E0%B8%A3%E0%B8%B1%E0%B8%A8%E0%B8%A1%E0%B8%B5" title="タイ語: รัศมี" lang="th" hreflang="th" data-title="รัศมี" data-language-autonym="ไทย" data-language-local-name="タイ語" 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/Radius" title="タガログ語: Radius" lang="tl" hreflang="tl" data-title="Radius" data-language-autonym="Tagalog" data-language-local-name="タガログ語" 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/Yar%C4%B1%C3%A7ap" title="トルコ語: Yarıçap" lang="tr" hreflang="tr" data-title="Yarıçap" data-language-autonym="Türkçe" data-language-local-name="トルコ語" 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/%D0%A0%D0%B0%D0%B4%D0%B8%D1%83%D1%81" title="タタール語: Радиус" lang="tt" hreflang="tt" data-title="Радиус" data-language-autonym="Татарча / tatarça" data-language-local-name="タタール語" 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%A0%D0%B0%D0%B4%D1%96%D1%83%D1%81" title="ウクライナ語: Радіус" lang="uk" hreflang="uk" data-title="Радіус" data-language-autonym="Українська" data-language-local-name="ウクライナ語" 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/%D8%B1%D8%AF%D8%A7%D8%B3" title="ウルドゥー語: رداس" lang="ur" hreflang="ur" data-title="رداس" data-language-autonym="اردو" data-language-local-name="ウルドゥー語" 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/Radius" title="ウズベク語: Radius" lang="uz" hreflang="uz" data-title="Radius" data-language-autonym="Oʻzbekcha / ўзбекча" data-language-local-name="ウズベク語" class="interlanguage-link-target"><span>Oʻzbekcha / ўзбекча</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/B%C3%A1n_k%C3%ADnh" title="ベトナム語: Bán kính" lang="vi" hreflang="vi" data-title="Bán kính" data-language-autonym="Tiếng Việt" data-language-local-name="ベトナム語" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-wuu mw-list-item"><a href="https://wuu.wikipedia.org/wiki/%E5%8D%8A%E5%BE%84" title="呉語: 半径" lang="wuu" hreflang="wuu" data-title="半径" data-language-autonym="吴语" data-language-local-name="呉語" 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%A8%D7%90%D7%93%D7%99%D7%95%D7%A1" title="イディッシュ語: ראדיוס" lang="yi" hreflang="yi" data-title="ראדיוס" data-language-autonym="ייִדיש" data-language-local-name="イディッシュ語" 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/%C3%8Cd%C3%A1m%C3%A9j%C3%AC_%C3%B2b%C3%ACr%C3%ACk%C3%ACti%C3%AC" title="ヨルバ語: Ìdáméjì òbìrìkìtiì" lang="yo" hreflang="yo" data-title="Ìdáméjì òbìrìkìtiì" data-language-autonym="Yorùbá" data-language-local-name="ヨルバ語" class="interlanguage-link-target"><span>Yorùbá</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E5%8D%8A%E5%BE%84" title="中国語: 半径" lang="zh" hreflang="zh" data-title="半径" data-language-autonym="中文" data-language-local-name="中国語" class="interlanguage-link-target"><span>中文</span></a></li><li class="interlanguage-link interwiki-zh-min-nan mw-list-item"><a href="https://zh-min-nan.wikipedia.org/wiki/Po%C3%A0%E2%81%BF-k%C3%A8ng" title="閩南語: Poàⁿ-kèng" lang="nan" hreflang="nan" data-title="Poàⁿ-kèng" data-language-autonym="閩南語 / Bân-lâm-gú" data-language-local-name="閩南語" 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/%E5%8D%8A%E5%BE%91" title="広東語: 半徑" lang="yue" hreflang="yue" data-title="半徑" data-language-autonym="粵語" data-language-local-name="広東語" 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/Q173817#sitelinks-wikipedia" title="言語間リンクを編集" class="wbc-editpage">リンクを編集</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="名前空間"> <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/%E5%8D%8A%E5%BE%84" title="本文を閲覧 [c]" accesskey="c"><span>ページ</span></a></li><li id="ca-talk" class="vector-tab-noicon mw-list-item"><a href="/wiki/%E3%83%8E%E3%83%BC%E3%83%88:%E5%8D%8A%E5%BE%84" rel="discussion" title="本文ページについての議論 [t]" accesskey="t"><span>ノート</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="別の言語に切り替える" > <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">日本語</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="表示"> <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/%E5%8D%8A%E5%BE%84"><span>閲覧</span></a></li><li id="ca-edit" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=%E5%8D%8A%E5%BE%84&action=edit" title="このページのソースコードを編集する [e]" accesskey="e"><span>編集</span></a></li><li id="ca-history" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=%E5%8D%8A%E5%BE%84&action=history" title="このページの過去の版 [h]" accesskey="h"><span>履歴表示</span></a></li> </ul> </div> </div> </nav> <nav class="vector-page-tools-landmark" aria-label="ページツール"> <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="ツール" > <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">ツール</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">ツール</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-page-tools.pin">サイドバーに移動</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-page-tools.unpin">非表示</button> </div> <div id="p-cactions" class="vector-menu mw-portlet mw-portlet-cactions emptyPortlet vector-has-collapsible-items" title="その他の操作" > <div class="vector-menu-heading"> 操作 </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/%E5%8D%8A%E5%BE%84"><span>閲覧</span></a></li><li id="ca-more-edit" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=%E5%8D%8A%E5%BE%84&action=edit" title="このページのソースコードを編集する [e]" accesskey="e"><span>編集</span></a></li><li id="ca-more-history" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=%E5%8D%8A%E5%BE%84&action=history"><span>履歴表示</span></a></li> </ul> </div> </div> <div id="p-tb" class="vector-menu mw-portlet mw-portlet-tb" > <div class="vector-menu-heading"> 全般 </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-whatlinkshere" class="mw-list-item"><a href="/wiki/%E7%89%B9%E5%88%A5:%E3%83%AA%E3%83%B3%E3%82%AF%E5%85%83/%E5%8D%8A%E5%BE%84" title="ここにリンクしている全ウィキページの一覧 [j]" accesskey="j"><span>リンク元</span></a></li><li id="t-recentchangeslinked" class="mw-list-item"><a href="/wiki/%E7%89%B9%E5%88%A5:%E9%96%A2%E9%80%A3%E3%83%9A%E3%83%BC%E3%82%B8%E3%81%AE%E6%9B%B4%E6%96%B0%E7%8A%B6%E6%B3%81/%E5%8D%8A%E5%BE%84" rel="nofollow" title="このページからリンクしているページの最近の更新 [k]" accesskey="k"><span>関連ページの更新状況</span></a></li><li id="t-upload" class="mw-list-item"><a href="/wiki/Wikipedia:%E3%83%95%E3%82%A1%E3%82%A4%E3%83%AB%E3%81%AE%E3%82%A2%E3%83%83%E3%83%97%E3%83%AD%E3%83%BC%E3%83%89" title="ファイルをアップロードする [u]" accesskey="u"><span>ファイルをアップロード</span></a></li><li id="t-specialpages" class="mw-list-item"><a href="/wiki/%E7%89%B9%E5%88%A5:%E7%89%B9%E5%88%A5%E3%83%9A%E3%83%BC%E3%82%B8%E4%B8%80%E8%A6%A7" title="特別ページの一覧 [q]" accesskey="q"><span>特別ページ</span></a></li><li id="t-permalink" class="mw-list-item"><a href="/w/index.php?title=%E5%8D%8A%E5%BE%84&oldid=92717028" title="このページのこの版への固定リンク"><span>この版への固定リンク</span></a></li><li id="t-info" class="mw-list-item"><a href="/w/index.php?title=%E5%8D%8A%E5%BE%84&action=info" title="このページについての詳細情報"><span>ページ情報</span></a></li><li id="t-cite" class="mw-list-item"><a href="/w/index.php?title=%E7%89%B9%E5%88%A5:%E3%81%93%E3%81%AE%E3%83%9A%E3%83%BC%E3%82%B8%E3%82%92%E5%BC%95%E7%94%A8&page=%E5%8D%8A%E5%BE%84&id=92717028&wpFormIdentifier=titleform" title="このページの引用方法"><span>このページを引用</span></a></li><li id="t-urlshortener" class="mw-list-item"><a href="/w/index.php?title=%E7%89%B9%E5%88%A5:UrlShortener&url=https%3A%2F%2Fja.wikipedia.org%2Fwiki%2F%25E5%258D%258A%25E5%25BE%2584"><span>短縮URLを取得する</span></a></li><li id="t-urlshortener-qrcode" class="mw-list-item"><a href="/w/index.php?title=%E7%89%B9%E5%88%A5:QrCode&url=https%3A%2F%2Fja.wikipedia.org%2Fwiki%2F%25E5%258D%258A%25E5%25BE%2584"><span>QRコードをダウンロード</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"> 印刷/書き出し </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=%E7%89%B9%E5%88%A5:%E3%83%96%E3%83%83%E3%82%AF&bookcmd=book_creator&referer=%E5%8D%8A%E5%BE%84"><span>ブックの新規作成</span></a></li><li id="coll-download-as-rl" class="mw-list-item"><a href="/w/index.php?title=%E7%89%B9%E5%88%A5:DownloadAsPdf&page=%E5%8D%8A%E5%BE%84&action=show-download-screen"><span>PDF 形式でダウンロード</span></a></li><li id="t-print" class="mw-list-item"><a href="/w/index.php?title=%E5%8D%8A%E5%BE%84&printable=yes" title="このページの印刷用ページ [p]" accesskey="p"><span>印刷用バージョン</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"> 他のプロジェクト </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/Radius" hreflang="en"><span>コモンズ</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/Q173817" title="関連付けられたデータリポジトリ項目へのリンク [g]" accesskey="g"><span>ウィキデータ項目</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="ページツール"> <div id="vector-page-tools-pinned-container" class="vector-pinned-container"> </div> </nav> <nav class="vector-appearance-landmark" aria-label="表示"> <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">表示</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-appearance.pin">サイドバーに移動</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-appearance.unpin">非表示</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">出典: フリー百科事典『ウィキペディア（Wikipedia）』</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="ja" dir="ltr"><style data-mw-deduplicate="TemplateStyles:r101346560">.mw-parser-output .hatnote{margin:0.5em 0;padding:3px 2em;background-color:transparent;border-bottom:1px solid #a2a9b1;font-size:90%}html.skin-theme-clientpref-night .mw-parser-output .hatnote>table{color:inherit}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .hatnote>table{color:inherit}}</style><div class="hatnote dablink noprint"><table style="width:100%; background:transparent;"> <tbody><tr><td style="width:25px;"><span typeof="mw:File"><a href="/wiki/%E3%83%95%E3%82%A1%E3%82%A4%E3%83%AB:Confusion_grey.svg" class="mw-file-description" title="曖昧さ回避"><img alt="曖昧さ回避" src="//upload.wikimedia.org/wikipedia/commons/thumb/f/fb/Confusion_grey.svg/25px-Confusion_grey.svg.png" decoding="async" width="25" height="19" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/fb/Confusion_grey.svg/38px-Confusion_grey.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/fb/Confusion_grey.svg/50px-Confusion_grey.svg.png 2x" data-file-width="260" data-file-height="200" /></a></span></td> <td>「<a href="/wiki/%E5%8D%8A%E5%BE%84_(%E3%82%B0%E3%83%A9%E3%83%95%E7%90%86%E8%AB%96)" class="mw-redirect" title="半径 (グラフ理論)">半径 (グラフ理論)</a>」あるいは「<span title="リンク先の項目はまだありません。新規の執筆や他言語版からの翻訳が望まれます。"><a href="/w/index.php?title=%E5%8D%8A%E7%9B%B4%E5%BE%84&action=edit&redlink=1" class="new" title="「半直径」 (存在しないページ)">半直径</a><span style="font-size: 0.77em; font-weight: normal;" class="noprint">（<a href="https://en.wikipedia.org/wiki/semidiameter" class="extiw" title="en:semidiameter">英語版</a>）</span></span>」とは異なります。</td> </tr></tbody></table></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/%E3%83%95%E3%82%A1%E3%82%A4%E3%83%AB:%E7%90%83%E3%81%AE%E5%8D%8A%E5%BE%84.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/c/c3/%E7%90%83%E3%81%AE%E5%8D%8A%E5%BE%84.png/220px-%E7%90%83%E3%81%AE%E5%8D%8A%E5%BE%84.png" decoding="async" width="220" height="220" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/c3/%E7%90%83%E3%81%AE%E5%8D%8A%E5%BE%84.png/330px-%E7%90%83%E3%81%AE%E5%8D%8A%E5%BE%84.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/c3/%E7%90%83%E3%81%AE%E5%8D%8A%E5%BE%84.png/440px-%E7%90%83%E3%81%AE%E5%8D%8A%E5%BE%84.png 2x" data-file-width="660" data-file-height="660" /></a><figcaption>球の半径</figcaption></figure> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/%E3%83%95%E3%82%A1%E3%82%A4%E3%83%AB:Circle-withsegments.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/0/03/Circle-withsegments.svg/220px-Circle-withsegments.svg.png" decoding="async" width="220" height="220" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/03/Circle-withsegments.svg/330px-Circle-withsegments.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/03/Circle-withsegments.svg/440px-Circle-withsegments.svg.png 2x" data-file-width="726" data-file-height="726" /></a><figcaption>円の<a href="/wiki/%E5%91%A8%E9%95%B7" title="周長">周囲</a> <span lang="en" class="texhtml mvar" style="font-style:italic;">C</span>(黒); 直径 <span lang="en" class="texhtml mvar" style="font-style:italic;">D</span>(水); 半径 <span lang="en" class="texhtml mvar" style="font-style:italic;">R</span>(赤); 中心（原点）<span lang="en" class="texhtml mvar" style="font-style:italic;">O</span>(紫)</figcaption></figure> <p><a href="/wiki/%E5%88%9D%E7%AD%89%E5%B9%BE%E4%BD%95%E5%AD%A6" title="初等幾何学">古典的な幾何学</a>では<a href="/wiki/%E5%86%86_(%E6%95%B0%E5%AD%A6)" title="円 (数学)">円</a>や<a href="/wiki/%E7%90%83%E9%9D%A2" title="球面">球</a>の<b>半径</b> (<a href="/wiki/%E8%8B%B1%E8%AA%9E" title="英語">英</a>: <span lang="en"><i>radius</i></span><sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>注 1<span class="cite-bracket">]</span></a></sup>) は、その中心から<a href="/wiki/%E5%91%A8%E9%95%B7" title="周長">周囲</a>へ渡した任意の<a href="/wiki/%E7%B7%9A%E5%88%86" title="線分">線分</a>や、その<a href="/wiki/%E9%95%B7%E3%81%95" title="長さ">長さ</a>である。 </p><p>これは「光線」や「<a href="/wiki/%E3%82%B9%E3%83%9D%E3%83%BC%E3%82%AF" title="スポーク">輻</a>」を意味する<a href="/wiki/%E3%83%A9%E3%83%86%E3%83%B3%E8%AA%9E" title="ラテン語">ラテン語</a>: <span lang="la">radius</span> に由来し、一点からあらゆる方向へ放射状に延びる<a href="/wiki/%E7%B7%9A%E5%88%86" title="線分">線分</a>（あるいは<a href="/wiki/%E5%8D%8A%E7%9B%B4%E7%B7%9A" class="mw-redirect" title="半直線">半直線</a> (ray)）を表している<sup id="cite_ref-radic_3-0" class="reference"><a href="#cite_note-radic-3"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup>。 </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="概要"><span id=".E6.A6.82.E8.A6.81"></span>概要</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=%E5%8D%8A%E5%BE%84&action=edit&section=1" title="節を編集: 概要"><span>編集</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>半径を文字で置くときは radius の頭文字をとった省略形の <span lang="en" class="texhtml">r</span> とするのが典型的である。この省略形は<a href="/wiki/1569%E5%B9%B4" title="1569年">1569年</a>に<span title="リンク先の項目はまだありません。新規の執筆や他言語版からの翻訳が望まれます。"><a href="/w/index.php?title=%E3%83%94%E3%82%A8%E3%83%BC%E3%83%AB%E3%83%BB%E3%83%A9%E3%83%A0%E3%82%B9&action=edit&redlink=1" class="new" title="「ピエール・ラムス」 (存在しないページ)">ピエール・ラムス</a><span style="font-size: 0.77em; font-weight: normal;" class="noprint">（<a href="https://en.wikipedia.org/wiki/Petrus_Ramus" class="extiw" title="en:Petrus Ramus">英語版</a>）</span></span>が初めて使用した<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup>。 </p><p>半径を二倍に延長して<a href="/wiki/%E7%9B%B4%E5%BE%84" class="mw-redirect" title="直径">直径</a>の大きさ <span lang="en" class="texhtml">d</span> を得る。つまり、<span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle d:=2r\qquad (\implies r={\frac {d}{2}})}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>d</mi> <mo>:=</mo> <mn>2</mn> <mi>r</mi> <mspace width="2em" /> <mo stretchy="false">(</mo> <mspace width="thickmathspace" /> <mo stretchy="false">⟹</mo> <mspace width="thickmathspace" /> <mi>r</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mi>d</mi> <mn>2</mn> </mfrac> </mrow> <mo stretchy="false">)</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle d:=2r\qquad (\implies r={\frac {d}{2}})}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/33a265314839f31db1682c688416eb866882a7dc" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:25.567ex; height:5.343ex;" alt="{\displaystyle d:=2r\qquad (\implies r={\frac {d}{2}})}"></span> の関係がある<sup id="cite_ref-mwd1_5-0" class="reference"><a href="#cite_note-mwd1-5"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup>。<a href="/wiki/%E5%91%A8%E9%95%B7" title="周長">周長</a>（<a href="/wiki/%E5%86%86%E5%91%A8" title="円周">円周</a>の長さ）<span lang="en" class="texhtml mvar" style="font-style:italic;">C</span> の円の半径は <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="{\textstyle r={\frac {C}{2\pi }}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="false" scriptlevel="0"> <mi>r</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mi>C</mi> <mrow> <mn>2</mn> <mi>π</mi> </mrow> </mfrac> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\textstyle r={\frac {C}{2\pi }}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/d9b0464f12c38153c645d48fb63e7565347625cd" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.171ex; width:6.747ex; height:3.676ex;" alt="{\textstyle r={\frac {C}{2\pi }}}"></span> で求められる。 </p><p><a href="/wiki/%E6%AD%A3%E5%A4%9A%E8%A7%92%E5%BD%A2" title="正多角形">正多角形</a>に対しては、単にその半径 (radius) と言った場合には<b>外半径</b>（<a href="/wiki/%E5%A4%96%E6%8E%A5%E5%86%86" title="外接円">外接円</a>の半径）の意味である<sup id="cite_ref-schaum_6-0" class="reference"><a href="#cite_note-schaum-6"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup>。正多角形の内半径（<a href="/wiki/%E5%86%85%E6%8E%A5%E5%86%86" title="内接円">内接円</a>の半径）は<a href="/wiki/%E8%BE%BA%E5%BF%83%E8%B7%9D%E9%9B%A2" title="辺心距離">辺心距離</a>と言う。 </p><p>中心を持たない幾何学的対象の場合には、<b>最小包含半径</b>（「最小包含円」や「<span title="リンク先の項目はまだありません。新規の執筆や他言語版からの翻訳が望まれます。"><a href="/w/index.php?title=%E6%9C%80%E5%B0%8F%E5%8C%85%E5%90%AB%E7%90%83&action=edit&redlink=1" class="new" title="「最小包含球」 (存在しないページ)">最小包含球</a><span style="font-size: 0.77em; font-weight: normal;" class="noprint">（<a href="https://en.wikipedia.org/wiki/Bounding_sphere" class="extiw" title="en:Bounding sphere">英語版</a>）</span></span>」の半径）という意味で単に「半径」(radius) ということもある。この場合の「半径」は（直径を通例の如くその図形の任意の二点間の距離の最大値として定義するならば）直径の半分よりも大きくなり得る。 </p><p>図形の<b>内半径</b> (inradius) はふつうその図形に含まれる円（または球）の最大半径の意味であるが、日常語として輪っか (ring) や筒 (tube) などの中空物体の内半径 (inner radius) は、その空洞部分の半径の意味で用いる。 </p><p><a href="/wiki/%E3%82%B0%E3%83%A9%E3%83%95%E7%90%86%E8%AB%96" title="グラフ理論">グラフ理論</a>において<a href="/wiki/%E5%8D%8A%E5%BE%84_(%E3%82%B0%E3%83%A9%E3%83%95%E7%90%86%E8%AB%96)" class="mw-redirect" title="半径 (グラフ理論)">グラフの半径</a> (radius) は、グラフの各頂点 <span lang="en" class="texhtml mvar" style="font-style:italic;">u</span> から測ったほかの頂点までの最大距離の <span lang="en" class="texhtml mvar" style="font-style:italic;">u</span> を任意の頂点を亙って動かしたときの最小値と定義される<sup id="cite_ref-yel_7-0" class="reference"><a href="#cite_note-yel-7"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup>。 </p> <div class="mw-heading mw-heading2"><h2 id="半径公式"><span id=".E5.8D.8A.E5.BE.84.E5.85.AC.E5.BC.8F"></span>半径公式</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=%E5%8D%8A%E5%BE%84&action=edit&section=2" title="節を編集: 半径公式"><span>編集</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>様々な図形に対し、半径は矛盾なく定義できて、その図形の他の部分の測度と何らかの関係性を持つ。 </p> <div class="mw-heading mw-heading3"><h3 id="円"><span id=".E5.86.86"></span>円</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=%E5%8D%8A%E5%BE%84&action=edit&section=3" title="節を編集: 円"><span>編集</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="rellink" style="margin-bottom: 0.5em; padding-left: 2em; font-size: 90%;" role="note">→「<a href="/wiki/%E5%86%86%E3%81%AE%E9%9D%A2%E7%A9%8D" title="円の面積">円の面積</a>」も参照</div> <p><a href="/wiki/%E9%9D%A2%E7%A9%8D" title="面積">面積</a>が <span lang="en" class="texhtml mvar" style="font-style:italic;">A</span> であるような<a href="/wiki/%E5%86%86_(%E6%95%B0%E5%AD%A6)" title="円 (数学)">円</a>の半径は <span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle r={\sqrt {\frac {A}{\pi }}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>r</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mfrac> <mi>A</mi> <mi>π</mi> </mfrac> </msqrt> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle r={\sqrt {\frac {A}{\pi }}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/697ac8af41c8d2ebd0f02f83f28e606381596f6a" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.338ex; width:9.05ex; height:6.343ex;" alt="{\displaystyle r={\sqrt {\frac {A}{\pi }}}}"></span> で求まる。 </p> <p><a href="/wiki/%E5%85%B1%E7%B7%9A" title="共線">同一直線上</a>にない三点 <span lang="en" class="texhtml"><i>P</i><sub>1</sub>, <i>P</i><sub>2</sub>, <i>P</i><sub>3</sub></span> を通る円の半径は <span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle r={\frac {|{\vec {OP_{1}}}-{\vec {OP_{3}}}|}{2\sin \theta }}\qquad (\theta =\angle P_{1}P_{2}P_{3})}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>r</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mrow class="MJX-TeXAtom-ORD"> <mo stretchy="false">|</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mover> <mrow> <mi>O</mi> <msub> <mi>P</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>1</mn> </mrow> </msub> </mrow> <mo stretchy="false">→</mo> </mover> </mrow> </mrow> <mo>−</mo> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mover> <mrow> <mi>O</mi> <msub> <mi>P</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>3</mn> </mrow> </msub> </mrow> <mo stretchy="false">→</mo> </mover> </mrow> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mo stretchy="false">|</mo> </mrow> </mrow> <mrow> <mn>2</mn> <mi>sin</mi> <mo>⁡</mo> <mi>θ</mi> </mrow> </mfrac> </mrow> <mspace width="2em" /> <mo stretchy="false">(</mo> <mi>θ</mi> <mo>=</mo> <mi mathvariant="normal">∠</mi> <msub> <mi>P</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>1</mn> </mrow> </msub> <msub> <mi>P</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msub> <msub> <mi>P</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>3</mn> </mrow> </msub> <mo stretchy="false">)</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle r={\frac {|{\vec {OP_{1}}}-{\vec {OP_{3}}}|}{2\sin \theta }}\qquad (\theta =\angle P_{1}P_{2}P_{3})}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/623b1437dafd83c2d25ce5503eecb89519e9797d" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.005ex; width:37.718ex; height:7.176ex;" alt="{\displaystyle r={\frac {|{\vec {OP_{1}}}-{\vec {OP_{3}}}|}{2\sin \theta }}\qquad (\theta =\angle P_{1}P_{2}P_{3})}"></span> で与えられる。この公式は<a href="/wiki/%E6%AD%A3%E5%BC%A6%E5%AE%9A%E7%90%86" title="正弦定理">正弦定理</a>に用いられる。</p><div class="rellink" style="margin-bottom: 0.5em; padding-left: 2em; font-size: 90%;" role="note">→詳細は「<a href="/wiki/%E6%AD%A3%E5%BC%A6%E5%AE%9A%E7%90%86" title="正弦定理">正弦定理</a>」を参照</div> <p>さらに、三点の座標が具体的に <span lang="en" class="texhtml">(<i>x</i><sub>1</sub>, <i>y</i><sub>1</sub>), (<i>x</i><sub>2</sub>, <i>y</i><sub>2</sub>), (<i>x</i><sub>3</sub>,<i>y</i><sub>3</sub>)</span> と与えられているならば、上式は <span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle r={\frac {\sqrt {[(x_{2}-x_{1})^{2}+(y_{2}-y_{1})^{2}][(x_{2}-x_{3})^{2}+(y_{2}-y_{3})^{2}][(x_{3}-x_{1})^{2}+(y_{3}-y_{1})^{2}]}}{2|x_{1}y_{2}+x_{2}y_{3}+x_{3}y_{1}-x_{1}y_{3}-x_{2}y_{1}-x_{3}y_{2}|}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>r</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <msqrt> <mo stretchy="false">[</mo> <mo stretchy="false">(</mo> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msub> <mo>−</mo> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>1</mn> </mrow> </msub> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>+</mo> <mo stretchy="false">(</mo> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msub> <mo>−</mo> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>1</mn> </mrow> </msub> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo stretchy="false">]</mo> <mo stretchy="false">[</mo> <mo stretchy="false">(</mo> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msub> <mo>−</mo> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>3</mn> </mrow> </msub> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>+</mo> <mo stretchy="false">(</mo> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msub> <mo>−</mo> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>3</mn> </mrow> </msub> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo stretchy="false">]</mo> <mo stretchy="false">[</mo> <mo stretchy="false">(</mo> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>3</mn> </mrow> </msub> <mo>−</mo> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>1</mn> </mrow> </msub> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>+</mo> <mo stretchy="false">(</mo> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>3</mn> </mrow> </msub> <mo>−</mo> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>1</mn> </mrow> </msub> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo stretchy="false">]</mo> </msqrt> <mrow> <mn>2</mn> <mrow class="MJX-TeXAtom-ORD"> <mo stretchy="false">|</mo> </mrow> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>1</mn> </mrow> </msub> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msub> <mo>+</mo> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msub> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>3</mn> </mrow> </msub> <mo>+</mo> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>3</mn> </mrow> </msub> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>1</mn> </mrow> </msub> <mo>−</mo> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>1</mn> </mrow> </msub> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>3</mn> </mrow> </msub> <mo>−</mo> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msub> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>1</mn> </mrow> </msub> <mo>−</mo> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>3</mn> </mrow> </msub> <msub> <mi>y</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msub> <mrow class="MJX-TeXAtom-ORD"> <mo stretchy="false">|</mo> </mrow> </mrow> </mfrac> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle r={\frac {\sqrt {[(x_{2}-x_{1})^{2}+(y_{2}-y_{1})^{2}][(x_{2}-x_{3})^{2}+(y_{2}-y_{3})^{2}][(x_{3}-x_{1})^{2}+(y_{3}-y_{1})^{2}]}}{2|x_{1}y_{2}+x_{2}y_{3}+x_{3}y_{1}-x_{1}y_{3}-x_{2}y_{1}-x_{3}y_{2}|}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/729326b799ed2cc75478ab6d68a6be083991b0bc" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.671ex; width:81.397ex; height:7.009ex;" alt="{\displaystyle r={\frac {\sqrt {[(x_{2}-x_{1})^{2}+(y_{2}-y_{1})^{2}][(x_{2}-x_{3})^{2}+(y_{2}-y_{3})^{2}][(x_{3}-x_{1})^{2}+(y_{3}-y_{1})^{2}]}}{2|x_{1}y_{2}+x_{2}y_{3}+x_{3}y_{1}-x_{1}y_{3}-x_{2}y_{1}-x_{3}y_{2}|}}}"></span> の形になる。 </p> <div class="mw-heading mw-heading3"><h3 id="正多角形"><span id=".E6.AD.A3.E5.A4.9A.E8.A7.92.E5.BD.A2"></span>正多角形</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=%E5%8D%8A%E5%BE%84&action=edit&section=4" title="節を編集: 正多角形"><span>編集</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="rellink" style="margin-bottom: 0.5em; padding-left: 2em; font-size: 90%;" role="note">→「<a href="/wiki/%E5%A4%96%E6%8E%A5%E5%86%86" title="外接円">外接円</a>」も参照</div> <table class="floatright"> <caption>小さい <span lang="en" class="texhtml mvar" style="font-style:italic;">n</span> に対する <span lang="en" class="texhtml mvar" style="font-style:italic;">R<sub>n</sub></span> </caption> <tbody><tr> <td> <table class="wikitable"> <tbody><tr> <th><span lang="en" class="texhtml mvar" style="font-style:italic;">n</span> </th> <th><span lang="en" class="texhtml"><i>R</i><sub><i>n</i></sub></span> </th></tr> <tr> <td>3</td> <td><span style="white-space:nowrap">0.577<span style="margin-left:0.2em">350...</span></span> </td></tr> <tr> <td>4</td> <td><span style="white-space:nowrap">0.707<span style="margin-left:0.2em">106...</span></span> </td></tr> <tr> <td>5</td> <td><span style="white-space:nowrap">0.850<span style="margin-left:0.2em">650...</span></span> </td></tr> <tr> <td>6</td> <td>1.0 </td></tr> <tr> <td>7</td> <td><span style="white-space:nowrap">1.152<span style="margin-left:0.2em">382...</span></span> </td></tr> <tr> <td>8</td> <td><span style="white-space:nowrap">1.306<span style="margin-left:0.2em">562...</span></span> </td></tr> <tr> <td>9</td> <td><span style="white-space:nowrap">1.461<span style="margin-left:0.2em">902...</span></span> </td></tr> <tr> <td>10</td> <td><span style="white-space:nowrap">1.618<span style="margin-left:0.2em">033...</span></span> </td></tr></tbody></table> </td> <td><figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/%E3%83%95%E3%82%A1%E3%82%A4%E3%83%AB:Regular_polygon_radius_square.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/3/39/Regular_polygon_radius_square.png/220px-Regular_polygon_radius_square.png" decoding="async" width="220" height="220" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/39/Regular_polygon_radius_square.png/330px-Regular_polygon_radius_square.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/39/Regular_polygon_radius_square.png/440px-Regular_polygon_radius_square.png 2x" data-file-width="704" data-file-height="704" /></a><figcaption><span lang="en" class="texhtml"><i>n</i> = 4</span>: 正方形の半径</figcaption></figure> </td></tr></tbody></table> <p>一辺の長さ <span lang="en" class="texhtml mvar" style="font-style:italic;">s</span> の正 <span lang="en" class="texhtml mvar" style="font-style:italic;">n</span>-角形の半径 <span lang="en" class="texhtml mvar" style="font-style:italic;">r</span> は <span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle r=R_{n}s\qquad {\Bigl (}R_{n}:={\frac {1}{2\sin({\frac {\pi }{n}})}}{\Bigr )}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>r</mi> <mo>=</mo> <msub> <mi>R</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>n</mi> </mrow> </msub> <mi>s</mi> <mspace width="2em" /> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-OPEN"> <mo maxsize="1.623em" minsize="1.623em">(</mo> </mrow> </mrow> <msub> <mi>R</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>n</mi> </mrow> </msub> <mo>:=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mrow> <mn>2</mn> <mi>sin</mi> <mo>⁡</mo> <mo stretchy="false">(</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mi>π</mi> <mi>n</mi> </mfrac> </mrow> <mo stretchy="false">)</mo> </mrow> </mfrac> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-CLOSE"> <mo maxsize="1.623em" minsize="1.623em">)</mo> </mrow> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle r=R_{n}s\qquad {\Bigl (}R_{n}:={\frac {1}{2\sin({\frac {\pi }{n}})}}{\Bigr )}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/b8e126e1d233425eba84036d7f9bc631f0897221" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.838ex; width:31.241ex; height:6.176ex;" alt="{\displaystyle r=R_{n}s\qquad {\Bigl (}R_{n}:={\frac {1}{2\sin({\frac {\pi }{n}})}}{\Bigr )}}"></span> で与えられる（小さい <span lang="en" class="texhtml mvar" style="font-style:italic;">n</span> に対する <span lang="en" class="texhtml mvar" style="font-style:italic;">R<sub>n</sub></span> の値を右の表にまとめておく）。 </p><p><span lang="en" class="texhtml"><i>s</i> = 1</span> のときには、<span lang="en" class="texhtml mvar" style="font-style:italic;">R<sub>n</sub></span> それ自身が対応する正 <span lang="en" class="texhtml mvar" style="font-style:italic;">n</span>-角形の半径を与えている。 </p> <div class="mw-heading mw-heading3"><h3 id="超立方体"><span id=".E8.B6.85.E7.AB.8B.E6.96.B9.E4.BD.93"></span>超立方体</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=%E5%8D%8A%E5%BE%84&action=edit&section=5" title="節を編集: 超立方体"><span>編集</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><span lang="en" class="texhtml mvar" style="font-style:italic;">d</span>-次元<a href="/wiki/%E8%B6%85%E7%AB%8B%E6%96%B9%E4%BD%93" title="超立方体">超立方体</a>の一辺の長さが <span lang="en" class="texhtml mvar" style="font-style:italic;">s</span> ならば、その半径は <span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle r={\frac {s}{2}}{\sqrt {d}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>r</mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mi>s</mi> <mn>2</mn> </mfrac> </mrow> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mi>d</mi> </msqrt> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle r={\frac {s}{2}}{\sqrt {d}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/a4c7830f8be586973f28ac4befb502e9c66892a1" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:9.297ex; height:4.676ex;" alt="{\displaystyle r={\frac {s}{2}}{\sqrt {d}}}"></span> を満たす。 </p> <div class="mw-heading mw-heading2"><h2 id="座標系の動径"><span id=".E5.BA.A7.E6.A8.99.E7.B3.BB.E3.81.AE.E5.8B.95.E5.BE.84"></span>座標系の動径</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=%E5%8D%8A%E5%BE%84&action=edit&section=6" title="節を編集: 座標系の動径"><span>編集</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>特別に固定された一点から放射状に走る<a href="/wiki/%E5%8D%8A%E7%9B%B4%E7%B7%9A" class="mw-redirect" title="半直線">半直線</a>という意味での radius は<b>動径</b>と呼ばれ、平面や三次元空間あるいはより一般の空間において、いくつかの座標系の構成成分の一つになる。例えば、動径成分が一定であるような点の軌跡は、円や球面を掃く。 </p> <div class="mw-heading mw-heading3"><h3 id="極座標系"><span id=".E6.A5.B5.E5.BA.A7.E6.A8.99.E7.B3.BB"></span>極座標系</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=%E5%8D%8A%E5%BE%84&action=edit&section=7" title="節を編集: 極座標系"><span>編集</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="rellink" style="margin-bottom: 0.5em; padding-left: 2em; font-size: 90%;" role="note">→詳細は「<a href="/wiki/%E6%A5%B5%E5%BA%A7%E6%A8%99%E7%B3%BB" title="極座標系">極座標系</a>」を参照</div> <p>極座標系は、<a href="/wiki/%E5%B9%B3%E9%9D%A2" title="平面">平面</a>上の各<a href="/wiki/%E7%82%B9_(%E5%B9%BE%E4%BD%95%E5%AD%A6)" class="mw-redirect" title="点 (幾何学)">点</a>が特別に固定された点からの<a href="/wiki/%E8%B7%9D%E9%9B%A2" title="距離">距離</a>と特別に固定された方向から測った<a href="/wiki/%E8%A7%92%E5%BA%A6" title="角度">角度</a>によって決定される、<a href="/wiki/%E4%BA%8C%E6%AC%A1%E5%85%83%E7%A9%BA%E9%96%93" class="mw-redirect" title="二次元空間">二次元</a>の<a href="/wiki/%E5%BA%A7%E6%A8%99%E7%B3%BB" class="mw-redirect" title="座標系">座標系</a>である。（<a href="/wiki/%E7%9B%B4%E4%BA%A4%E5%BA%A7%E6%A8%99%E7%B3%BB" title="直交座標系">直交座標系</a>における<a href="/wiki/%E5%8E%9F%E7%82%B9_(%E6%95%B0%E5%AD%A6)" title="原点 (数学)">原点</a>に対応する）固定された点はこの座標系の<b>極</b> (<i>pole</i>) と言い、固定された方向へ極から出る<a href="/wiki/%E5%8D%8A%E7%9B%B4%E7%B7%9A" class="mw-redirect" title="半直線">半直線</a>を<b>極線</b> (<i>polar axis</i>; 極軸), <b>原線</b> (<i>primitive axis</i>) または<b>始線</b> (<i>initial axis</i>) という。極からの距離を<b>動径座標</b> (<i>radial coordinate</i>) あるいは<b>動径</b> (<i>radius</i>) などと呼び、極線から測った角を<b>偏角座標</b> (<i>angular coordinate</i>)、<b>極角</b> (<i>polar angle</i>) あるいは<b><a href="/wiki/%E6%96%B9%E4%BD%8D%E8%A7%92" title="方位角">方位角</a></b> (<i>azimuth</i>) などと呼ぶ<sup id="cite_ref-brown_8-0" class="reference"><a href="#cite_note-brown-8"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup>。 </p> <div class="mw-heading mw-heading3"><h3 id="円筒座標系"><span id=".E5.86.86.E7.AD.92.E5.BA.A7.E6.A8.99.E7.B3.BB"></span>円筒座標系</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=%E5%8D%8A%E5%BE%84&action=edit&section=8" title="節を編集: 円筒座標系"><span>編集</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="rellink" style="margin-bottom: 0.5em; padding-left: 2em; font-size: 90%;" role="note">→詳細は「<a href="/wiki/%E5%86%86%E7%AD%92%E5%BA%A7%E6%A8%99%E7%B3%BB" title="円筒座標系">円筒座標系</a>」を参照</div> <p>円筒座標系では、基準となる固定された軸とその軸に直交する基準平面が存在する。この座標系の「原点」は基準軸と基準面との交点を言い、三つの座標成分すべてを零としたときの点として指定することができる。 </p><p>基準面上では原点を極とする極座標系が入っており、その極座標系に関する<b>極線</b>が基準面上にあるから、基準面に直交する基準軸はそれと区別するために、<b>円筒軸</b> (<i>cylindrical axis</i>) や<b>緯線軸</b> (<i>longitudinal axis</i>) などと呼ぶが、基準面を水平面と考えるときには<b>縦軸</b>、基準面を垂直面と考えるときには<b>横軸</b>や<b>前後軸</b>のようにも呼び、名称は様々である。 </p><p>円筒軸からの距離を<b>動径距離</b> (<i>radial distance</i>) や<b>動径</b> (<i>radius</i>) と言い、円筒軸回りの偏角座標をしばしば<b>角度位置</b> (<i>angular position</i>) や<b><a href="/wiki/%E6%96%B9%E4%BD%8D%E8%A7%92" title="方位角">方位角</a></b> (<i>azimuth</i>) と呼ぶ。考えている点を通り基準面に平行な平面上で、動径と方位角は二次元の<a href="/wiki/%E6%A5%B5%E5%BA%A7%E6%A8%99%E7%B3%BB" title="極座標系">極座標系</a>を定めるから、動径成分と方位角成分を併せて「極座標成分」(<i>polar coordinates</i>) と呼ぶ。残る第三の成分は、<b>緯度</b> (<i>longitudinal position</i><sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup>) や<b>軸位置</b> (<i>axial position</i>.<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup>) などと呼ばれ、あるいは基準面を水平面と見たときには<b>高さ</b> (<i>height</i>) や<b>高度</b> (<i>altitude</i>) などとも呼ぶ。 </p> <div class="mw-heading mw-heading3"><h3 id="球面座標系"><span id=".E7.90.83.E9.9D.A2.E5.BA.A7.E6.A8.99.E7.B3.BB"></span>球面座標系</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=%E5%8D%8A%E5%BE%84&action=edit&section=9" title="節を編集: 球面座標系"><span>編集</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="rellink" style="margin-bottom: 0.5em; padding-left: 2em; font-size: 90%;" role="note">→詳細は「<a href="/wiki/%E7%90%83%E9%9D%A2%E5%BA%A7%E6%A8%99%E7%B3%BB" title="球面座標系">球面座標系</a>」を参照</div> <p>球面座標系では、<b>動径</b>の大きさは固定された原点からの距離を記述するものになる。この座標系での点の位置は、動径成分以外に、固定された天頂方向 (<i>zenith direction</i>) から動径方向へ測った極角である<b>天頂角</b> (<i>zenith angle</i>) と、原点を通り天頂方向に直交する基準平面上への動径方向の直交射影と基準平面上の基準方向の成す角である<b><a href="/wiki/%E6%96%B9%E4%BD%8D%E8%A7%92" title="方位角">方位角</a></b> (<i>azimuth angle</i>) で決まる。 </p> <div class="mw-heading mw-heading2"><h2 id="脚注"><span id=".E8.84.9A.E6.B3.A8"></span>脚注</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=%E5%8D%8A%E5%BE%84&action=edit&section=10" title="節を編集: 脚注"><span>編集</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="noprint" style="float:right; font-size:90%;">[<a href="/wiki/Help:%E8%84%9A%E6%B3%A8/%E8%AA%AD%E8%80%85%E5%90%91%E3%81%91" title="Help:脚注/読者向け"><span title="この欄の操作法">脚注の使い方</span></a>]</div> <div class="mw-heading mw-heading3"><h3 id="注釈"><span id=".E6.B3.A8.E9.87.88"></span>注釈</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=%E5%8D%8A%E5%BE%84&action=edit&section=11" title="節を編集: 注釈"><span>編集</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="reflist" style="list-style-type: decimal;"> <ol class="references"> <li id="cite_note-2"><b><a href="#cite_ref-2">^</a></b> <span class="reference-text">複数形は <i>radii</i>（ラテン語式）だが、稀に英語式で <i>radiuses</i> とすることもある<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup></span> </li> </ol></div> <div class="mw-heading mw-heading3"><h3 id="出典"><span id=".E5.87.BA.E5.85.B8"></span>出典</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=%E5%8D%8A%E5%BE%84&action=edit&section=12" title="節を編集: 出典"><span>編集</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="reflist" style="-moz-column-count:auto; -webkit-column-count:auto; column-count:auto; -moz-column-width: 30em; -webkit-column-width: 30em; column-width: 30em; list-style-type: decimal;"> <ol class="references"> <li id="cite_note-1"><b><a href="#cite_ref-1">^</a></b> <span class="reference-text"><cite class="citation web" style="font-style:normal">“<a rel="nofollow" class="external text" href="http://www.merriam-webster.com/dictionary/radius">Radius - Definition and More from the Free Merriam-Webster Dictionary</a>”.  Merriam-webster.com. <span title="">2012年5月22日</span>閲覧。</cite></span> </li> <li id="cite_note-radic-3"><b><a href="#cite_ref-radic_3-0">^</a></b> <span class="reference-text"><a rel="nofollow" class="external text" href="http://dictionary.reference.com/browse/Radius">Definition of Radius</a> at dictionary.reference.com. Accessed on 2009-08-08.</span> </li> <li id="cite_note-4"><b><a href="#cite_ref-4">^</a></b> <span class="reference-text"><cite style="font-style:normal" class="citation" id="CITEREF黒木哲徳2021">黒木哲徳『なっとくする数学記号』講談社〈ブルーバックス〉、2021年、32頁。<style data-mw-deduplicate="TemplateStyles:r101121245">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation.cs-ja1 q,.mw-parser-output .citation.cs-ja2 q{quotes:"「""」""『""』"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free a,.mw-parser-output .citation .cs1-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited a,.mw-parser-output .id-lock-registration a,.mw-parser-output .citation .cs1-lock-limited a,.mw-parser-output .citation .cs1-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription a,.mw-parser-output .citation .cs1-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:var(--color-success,#3a3);margin-left:0.3em}.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}</style><a href="/wiki/ISBN" title="ISBN">ISBN</a> <a href="/wiki/%E7%89%B9%E5%88%A5:%E6%96%87%E7%8C%AE%E8%B3%87%E6%96%99/9784065225509" title="特別:文献資料/9784065225509">9784065225509</a>。</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=%E3%81%AA%E3%81%A3%E3%81%A8%E3%81%8F%E3%81%99%E3%82%8B%E6%95%B0%E5%AD%A6%E8%A8%98%E5%8F%B7&rft.aulast=%E9%BB%92%E6%9C%A8%E5%93%B2%E5%BE%B3&rft.au=%E9%BB%92%E6%9C%A8%E5%93%B2%E5%BE%B3&rft.date=2021&rft.series=%E3%83%96%E3%83%AB%E3%83%BC%E3%83%90%E3%83%83%E3%82%AF%E3%82%B9&rft.pages=32%E9%A0%81&rft.pub=%E8%AC%9B%E8%AB%87%E7%A4%BE&rft.isbn=9784065225509&rfr_id=info:sid/ja.wikipedia.org:%E5%8D%8A%E5%BE%84"><span style="display: none;"> </span></span></span> </li> <li id="cite_note-mwd1-5"><b><a href="#cite_ref-mwd1_5-0">^</a></b> <span class="reference-text"> <a rel="nofollow" class="external text" href="http://www.mathwords.com/r/radius_of_a_circle_or_sphere.htm">Definition of radius</a> at mathwords.com. Accessed on 2009-08-08.</span> </li> <li id="cite_note-schaum-6"><b><a href="#cite_ref-schaum_6-0">^</a></b> <span class="reference-text">Barnett Rich, Christopher Thomas (2008), <i>Schaum's Outline of Geometry</i>, 4th edition, 326 pages. McGraw-Hill Professional. <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r101121245"><a href="/wiki/ISBN" title="ISBN">ISBN</a> <a href="/wiki/%E7%89%B9%E5%88%A5:%E6%96%87%E7%8C%AE%E8%B3%87%E6%96%99/0-07-154412-7" title="特別:文献資料/0-07-154412-7">0-07-154412-7</a>, <a href="/wiki/%E7%89%B9%E5%88%A5:%E6%96%87%E7%8C%AE%E8%B3%87%E6%96%99/978-0-07-154412-2" title="特別:文献資料/978-0-07-154412-2">978-0-07-154412-2</a>. <a rel="nofollow" class="external text" href="https://books.google.com/books?id=ab8lZG2yubcC">Online version</a> accessed on 2009-08-08.</span> </li> <li id="cite_note-yel-7"><b><a href="#cite_ref-yel_7-0">^</a></b> <span class="reference-text">Jonathan L. Gross, Jay Yellen (2006), <i>Graph theory and its applications</i>. 2nd edition, 779 pages; CRC Press. <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r101121245"><a href="/wiki/ISBN" title="ISBN">ISBN</a> <a href="/wiki/%E7%89%B9%E5%88%A5:%E6%96%87%E7%8C%AE%E8%B3%87%E6%96%99/1-58488-505-X" title="特別:文献資料/1-58488-505-X">1-58488-505-X</a>, <a href="/wiki/%E7%89%B9%E5%88%A5:%E6%96%87%E7%8C%AE%E8%B3%87%E6%96%99/9781584885054" title="特別:文献資料/9781584885054">9781584885054</a>. <a rel="nofollow" class="external text" href="https://books.google.com/books?id=unEloQ_sYmkC">Online version</a> accessed on 2009-08-08.</span> </li> <li id="cite_note-brown-8"><b><a href="#cite_ref-brown_8-0">^</a></b> <span class="reference-text"><cite style="font-style:normal" class="citation book">Brown, Richard G. (1997). Andrew M. Gleason. ed. <i>Advanced Mathematics: Precalculus with Discrete Mathematics and Data Analysis</i>. Evanston, Illinois: McDougal Littell. <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r101121245"><a href="/wiki/ISBN" title="ISBN">ISBN</a> <a href="/wiki/%E7%89%B9%E5%88%A5:%E6%96%87%E7%8C%AE%E8%B3%87%E6%96%99/0-395-77114-5" title="特別:文献資料/0-395-77114-5">0-395-77114-5</a></cite><span class="Z3988" title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Advanced+Mathematics%3A+Precalculus+with+Discrete+Mathematics+and+Data+Analysis&rft.aulast=Brown&rft.aufirst=Richard+G.&rft.au=Brown%2C%26%2332%3BRichard+G.&rft.date=1997&rft.place=Evanston%2C+Illinois&rft.pub=McDougal+Littell&rft.isbn=0-395-77114-5&rfr_id=info:sid/ja.wikipedia.org:%E5%8D%8A%E5%BE%84"><span style="display: none;"> </span></span></span> </li> <li id="cite_note-9"><b><a href="#cite_ref-9">^</a></b> <span class="reference-text"><cite style="font-style:normal" class="citation journal">Krafft, C.; Volokitin, A. S. (1 January 2002). <a rel="nofollow" class="external text" href="https://archive.is/20130414005110/http://pop.aip.org/resource/1/phpaen/v9/i6/p2786_s1?isAuthorized=no">“Resonant electron beam interaction with several lower hybrid waves”</a>. <i>Physics of Plasmas</i> <b>9</b> (6): 2786–2797. <a href="/wiki/Bibcode_(%E8%AD%98%E5%88%A5%E5%AD%90)" class="mw-redirect" title="Bibcode (識別子)">Bibcode</a>: <a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2002PhPl....9.2786K/abstract">2002PhPl....9.2786K</a>. <a href="/wiki/Doi_(%E8%AD%98%E5%88%A5%E5%AD%90)" class="mw-redirect" title="Doi (識別子)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1063%2F1.1465420">10.1063/1.1465420</a>. <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r101121245"><a href="/wiki/ISSN" title="ISSN">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/ja/search?fq=x0:jrnl&q=n2:1089-7674">1089-7674</a>.  <a rel="nofollow" class="external text" href="http://pop.aip.org/resource/1/phpaen/v9/i6/p2786_s1?isAuthorized=no">オリジナル</a>の14 April 2013時点におけるアーカイブ。<span style="display:none;">. <a rel="nofollow" class="external free" href="https://archive.is/20130414005110/http://pop.aip.org/resource/1/phpaen/v9/i6/p2786_s1?isAuthorized=no">https://archive.is/20130414005110/http://pop.aip.org/resource/1/phpaen/v9/i6/p2786_s1?isAuthorized=no</a></span> <span class="reference-accessdate"><span title="">9 February 2013</span>閲覧</span>. "...in cylindrical coordinates (<i>r</i>,<i>θ</i>,<i>z</i>) ... and Z=v<sub>bz</sub>t is the longitudinal position..."</cite><span class="Z3988" title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.atitle=Resonant+electron+beam+interaction+with+several+lower+hybrid+waves&rft.jtitle=Physics+of+Plasmas&rft.aulast=Krafft&rft.aufirst=C.&rft.au=Krafft%2C%26%2332%3BC.&rft.au=Volokitin%2C%26%2332%3BA.+S.&rft.date=1+January+2002&rft.volume=9&rft.issue=6&rft.pages=2786%E2%80%932797&rft_id=info:bibcode/2002PhPl....9.2786K&rft_id=info:doi/10.1063%2F1.1465420&rft.issn=1089-7674&rft_id=https%3A%2F%2Farchive.is%2F20130414005110%2Fhttp%3A%2F%2Fpop.aip.org%2Fresource%2F1%2Fphpaen%2Fv9%2Fi6%2Fp2786_s1%3FisAuthorized%3Dno&rfr_id=info:sid/ja.wikipedia.org:%E5%8D%8A%E5%BE%84"><span style="display: none;"> </span></span></span> </li> <li id="cite_note-10"><b><a href="#cite_ref-10">^</a></b> <span class="reference-text">Alexander Groisman and Victor Steinberg (1997), <i>Solitary Vortex Pairs in Viscoelastic Couette Flow</i>. Physical Review Letters, volume 78, number 8, 1460–1463. <a href="/wiki/Doi_(%E8%AD%98%E5%88%A5%E5%AD%90)" class="mw-redirect" title="Doi (識別子)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1103%2FPhysRevLett.78.1460">10.1103/PhysRevLett.78.1460</a> "[...]where <i>r</i>, <i>θ</i>, and <i>z</i> are cylindrical coordinates [...] as a function of axial position[...]"</span> </li> </ol></div> <div class="mw-heading mw-heading2"><h2 id="関連項目"><span id=".E9.96.A2.E9.80.A3.E9.A0.85.E7.9B.AE"></span>関連項目</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=%E5%8D%8A%E5%BE%84&action=edit&section=13" title="節を編集: 関連項目"><span>編集</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r94202605">.mw-parser-output .side-box{margin:4px 0;box-sizing:border-box;border:1px solid #aaa;font-size:88%;line-height:1.25em;background-color:#f9f9f9;display:flow-root}.mw-parser-output .side-box-abovebelow,.mw-parser-output .side-box-text{padding:0.25em 0.9em}.mw-parser-output .side-box-image{padding:2px 0 2px 0.9em;text-align:center}.mw-parser-output .side-box-imageright{padding:2px 0.9em 2px 0;text-align:center}@media(min-width:500px){.mw-parser-output .side-box-flex{display:flex;align-items:center}.mw-parser-output .side-box-text{flex:1}}@media(min-width:720px){.mw-parser-output .side-box{width:238px}.mw-parser-output .side-box-right{clear:right;float:right;margin-left:1em}.mw-parser-output .side-box-left{margin-right:1em}}</style><div class="side-box side-box-right plainlinks sistersitebox noprint" style="width:22em;"> <div class="side-box-flex"> <div class="side-box-image"><span class="noviewer" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/f/ff/Wikidata-logo.svg/40px-Wikidata-logo.svg.png" decoding="async" width="40" height="22" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/ff/Wikidata-logo.svg/60px-Wikidata-logo.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/ff/Wikidata-logo.svg/80px-Wikidata-logo.svg.png 2x" data-file-width="1050" data-file-height="590" /></span></span></div> <div class="side-box-text plainlist" style="font-size:100%;"><a href="/wiki/%E3%82%A6%E3%82%A3%E3%82%AD%E3%83%87%E3%83%BC%E3%82%BF" title="ウィキデータ">ウィキデータ</a>には半径のプロパティである<b><a href="https://www.wikidata.org/wiki/Special:EntityPage/P2120" class="extiw" title="d:Special:EntityPage/P2120">半径</a></b>があります。（<a href="https://www.wikidata.org/wiki/Special:WhatLinksHere/Property:P2120" class="extiw" title="d:Special:WhatLinksHere/Property:P2120"> 使用状況</a>）</div></div> </div> <div class="div-col columns column-count column-count-" style="-moz-column-count:; -webkit-column-count:; column-count:; -moz-column-width: 18em; -webkit-column-width: 18em; column-width: 18em;"> <ul><li><span title="リンク先の項目はまだありません。新規の執筆や他言語版からの翻訳が望まれます。"><a href="/w/index.php?title=%E6%9B%B2%E3%81%92%E5%8D%8A%E5%BE%84&action=edit&redlink=1" class="new" title="「曲げ半径」 (存在しないページ)">曲げ半径</a><span style="font-size: 0.77em; font-weight: normal;" class="noprint">（<a href="https://en.wikipedia.org/wiki/Bend_radius" class="extiw" title="en:Bend radius">英語版</a>）</span></span></li> <li><span title="リンク先の項目はまだありません。新規の執筆や他言語版からの翻訳が望まれます。"><a href="/w/index.php?title=%E5%85%85%E5%A1%AB%E5%8D%8A%E5%BE%84&action=edit&redlink=1" class="new" title="「充填半径」 (存在しないページ)">充填半径</a><span style="font-size: 0.77em; font-weight: normal;" class="noprint">（<a href="https://en.wikipedia.org/wiki/Filling_radius" class="extiw" title="en:Filling radius">英語版</a>）</span></span> in Riemannian geometry</li> <li><a href="/wiki/%E5%8F%8E%E6%9D%9F%E5%8D%8A%E5%BE%84" title="収束半径">収束半径</a></li> <li><span title="リンク先の項目はまだありません。新規の執筆や他言語版からの翻訳が望まれます。"><a href="/w/index.php?title=%E5%87%B8%E6%80%A7%E5%8D%8A%E5%BE%84&action=edit&redlink=1" class="new" title="「凸性半径」 (存在しないページ)">凸性半径</a><span style="font-size: 0.77em; font-weight: normal;" class="noprint">（<a href="https://en.wikipedia.org/wiki/Radius_of_convexity" class="extiw" title="en:Radius of convexity">英語版</a>）</span></span></li> <li><a href="/wiki/%E6%9B%B2%E7%8E%87%E5%8D%8A%E5%BE%84" class="mw-redirect" title="曲率半径">曲率半径</a></li> <li><a href="/wiki/%E6%96%AD%E9%9D%A2%E5%9B%9E%E8%BB%A2%E5%8D%8A%E5%BE%84" title="断面回転半径">断面回転半径</a></li> <li><span title="リンク先の項目はまだありません。新規の執筆や他言語版からの翻訳が望まれます。"><a href="/w/index.php?title=%E5%8D%8A%E7%9B%B4%E5%BE%84&action=edit&redlink=1" class="new" title="「半直径」 (存在しないページ)">半直径</a><span style="font-size: 0.77em; font-weight: normal;" class="noprint">（<a href="https://en.wikipedia.org/wiki/Semidiameter" class="extiw" title="en:Semidiameter">英語版</a>）</span></span></li></ul> </div> <div class="mw-heading mw-heading2"><h2 id="外部リンク"><span id=".E5.A4.96.E9.83.A8.E3.83.AA.E3.83.B3.E3.82.AF"></span>外部リンク</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=%E5%8D%8A%E5%BE%84&action=edit&section=14" title="節を編集: 外部リンク"><span>編集</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><span class="citation mathworld" id="Reference-Mathworld-Radius"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r101121245"><cite id="CITEREFWeisstein" class="citation web cs1 cs1-prop-foreign-lang-source">Weisstein, Eric W. <a rel="nofollow" class="external text" href="https://mathworld.wolfram.com/Radius.html">"Radius"</a>. <i>mathworld.wolfram.com</i> (英語).</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=mathworld.wolfram.com&rft.atitle=Radius&rft.aulast=Weisstein&rft.aufirst=Eric+W.&rft_id=https%3A%2F%2Fmathworld.wolfram.com%2FRadius.html&rfr_id=info%3Asid%2Fja.wikipedia.org%3A%E5%8D%8A%E5%BE%84" class="Z3988"></span></span></li> <li><a rel="nofollow" class="external text" href="https://ncatlab.org/nlab/show/radius">radius</a> in <i><a href="https://en.wikipedia.org/wiki/nLab" class="extiw" title="en:nLab">nLab</a></i></li> <li><i><a rel="nofollow" class="external text" href="https://planetmath.org/radius">radius</a></i> - <a href="/wiki/PlanetMath" title="PlanetMath">PlanetMath</a>.<span class="tmpl-language-icon" style="font-size:0.95em; font-weight:bold; color:#555">（英語）</span></li> <li><a href="//www.proofwiki.org/wiki/Definition:Radius" class="extiw" title="proofwiki:Definition:Radius">Definition:Radius</a> at <a rel="nofollow" class="external text" href="https://proofwiki.org/">ProofWiki</a></li> <li><cite style="font-style:normal" class="citation" id="CITEREFBSE-32001">BSE-3 (2001), <a rel="nofollow" class="external text" href="https://www.encyclopediaofmath.org/index.php?title=Radius">“Radius”</a>, in Hazewinkel, Michiel, <i><a href="https://en.wikipedia.org/wiki/Encyclopedia_of_Mathematics" class="extiw" title="en:Encyclopedia of Mathematics">Encyclopedia of Mathematics</a></i>, Springer, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r101121245"><a href="/wiki/ISBN" title="ISBN">ISBN</a> <a href="/wiki/%E7%89%B9%E5%88%A5:%E6%96%87%E7%8C%AE%E8%B3%87%E6%96%99/978-1-55608-010-4" title="特別:文献資料/978-1-55608-010-4">978-1-55608-010-4</a><span style="display:none;">, <a rel="nofollow" class="external free" href="https://www.encyclopediaofmath.org/index.php?title=Radius">https://www.encyclopediaofmath.org/index.php?title=Radius</a></span></cite><span class="Z3988" title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.btitle=Radius&rft.atitle=%5B%5B%3Aen%3AEncyclopedia+of+Mathematics%7CEncyclopedia+of+Mathematics%5D%5D&rft.aulast=BSE-3&rft.au=BSE-3&rft.date=2001&rft.pub=Springer&rft.isbn=978-1-55608-010-4&rft_id=&rfr_id=info:sid/ja.wikipedia.org:%E5%8D%8A%E5%BE%84"><span style="display: none;"> </span></span></li> <li><cite style="font-style:normal" class="citation" id="CITEREFBSE-32001">BSE-3 (2001), <a rel="nofollow" class="external text" href="https://www.encyclopediaofmath.org/index.php?title=Radius_vector">“Radius vector”</a>, in Hazewinkel, Michiel, <i><a href="https://en.wikipedia.org/wiki/Encyclopedia_of_Mathematics" class="extiw" title="en:Encyclopedia of Mathematics">Encyclopedia of Mathematics</a></i>, Springer, <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r101121245"><a href="/wiki/ISBN" title="ISBN">ISBN</a> <a href="/wiki/%E7%89%B9%E5%88%A5:%E6%96%87%E7%8C%AE%E8%B3%87%E6%96%99/978-1-55608-010-4" title="特別:文献資料/978-1-55608-010-4">978-1-55608-010-4</a><span style="display:none;">, <a rel="nofollow" class="external free" href="https://www.encyclopediaofmath.org/index.php?title=Radius_vector">https://www.encyclopediaofmath.org/index.php?title=Radius_vector</a></span></cite><span class="Z3988" title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.btitle=Radius+vector&rft.atitle=%5B%5B%3Aen%3AEncyclopedia+of+Mathematics%7CEncyclopedia+of+Mathematics%5D%5D&rft.aulast=BSE-3&rft.au=BSE-3&rft.date=2001&rft.pub=Springer&rft.isbn=978-1-55608-010-4&rft_id=&rfr_id=info:sid/ja.wikipedia.org:%E5%8D%8A%E5%BE%84"><span style="display: none;"> </span></span></li></ul> <div role="navigation" class="navbox authority-control" 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" class="navbox-group" style="width:1%"><a href="/wiki/Help:%E5%85%B8%E6%8B%A0%E7%AE%A1%E7%90%86" title="Help:典拠管理">典拠管理データベース</a>: 国立図書館 <span class="mw-valign-text-top noprint" typeof="mw:File/Frameless"><a href="https://www.wikidata.org/wiki/Q173817#identifiers" title="ウィキデータを編集"><img alt="ウィキデータを編集" src="//upload.wikimedia.org/wikipedia/commons/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/10px-OOjs_UI_icon_edit-ltr-progressive.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/15px-OOjs_UI_icon_edit-ltr-progressive.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/20px-OOjs_UI_icon_edit-ltr-progressive.svg.png 2x" data-file-width="20" data-file-height="20" /></a></span></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"> <ul><li><span class="uid"><a rel="nofollow" class="external text" href="https://d-nb.info/gnd/4451175-9">ドイツ</a></span></li> <li><span class="uid"><a rel="nofollow" class="external text" href="http://olduli.nli.org.il/F/?func=find-b&local_base=NLX10&find_code=UID&request=987007535067505171">イスラエル</a></span></li> <li><span class="uid"><a rel="nofollow" class="external text" href="https://id.loc.gov/authorities/sh2003001067">アメリカ</a></span></li></ul> </div></td></tr></tbody></table></div>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?type=1x1" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">「<a dir="ltr" href="https://ja.wikipedia.org/w/index.php?title=半径&oldid=92717028">https://ja.wikipedia.org/w/index.php?title=半径&oldid=92717028</a>」から取得</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/wiki/%E7%89%B9%E5%88%A5:%E3%82%AB%E3%83%86%E3%82%B4%E3%83%AA" title="特別:カテゴリ">カテゴリ</a>: <ul><li><a href="/wiki/Category:%E5%B9%BE%E4%BD%95%E5%AD%A6" title="Category:幾何学">幾何学</a></li><li><a href="/wiki/Category:%E5%88%9D%E7%AD%89%E6%95%B0%E5%AD%A6" title="Category:初等数学">初等数学</a></li><li><a href="/wiki/Category:%E9%95%B7%E3%81%95" title="Category:長さ">長さ</a></li><li><a href="/wiki/Category:%E6%95%B0%E5%AD%A6%E3%81%AB%E9%96%A2%E3%81%99%E3%82%8B%E8%A8%98%E4%BA%8B" title="Category:数学に関する記事">数学に関する記事</a></li></ul></div><div id="mw-hidden-catlinks" class="mw-hidden-catlinks mw-hidden-cats-hidden">隠しカテゴリ: <ul><li><a href="/wiki/Category:GND%E8%AD%98%E5%88%A5%E5%AD%90%E3%81%8C%E6%8C%87%E5%AE%9A%E3%81%95%E3%82%8C%E3%81%A6%E3%81%84%E3%82%8B%E8%A8%98%E4%BA%8B" title="Category:GND識別子が指定されている記事">GND識別子が指定されている記事</a></li><li><a href="/wiki/Category:J9U%E8%AD%98%E5%88%A5%E5%AD%90%E3%81%8C%E6%8C%87%E5%AE%9A%E3%81%95%E3%82%8C%E3%81%A6%E3%81%84%E3%82%8B%E8%A8%98%E4%BA%8B" title="Category:J9U識別子が指定されている記事">J9U識別子が指定されている記事</a></li><li><a href="/wiki/Category:LCCN%E8%AD%98%E5%88%A5%E5%AD%90%E3%81%8C%E6%8C%87%E5%AE%9A%E3%81%95%E3%82%8C%E3%81%A6%E3%81%84%E3%82%8B%E8%A8%98%E4%BA%8B" title="Category:LCCN識別子が指定されている記事">LCCN識別子が指定されている記事</a></li></ul></div></div> </div> </main> </div> <div class="mw-footer-container"> <footer id="footer" class="mw-footer" > <ul id="footer-info"> <li id="footer-info-lastmod"> 最終更新 2022年12月3日 (土) 03:09 （日時は<a href="/wiki/%E7%89%B9%E5%88%A5:%E5%80%8B%E4%BA%BA%E8%A8%AD%E5%AE%9A#mw-prefsection-rendering" title="特別:個人設定">個人設定</a>で未設定ならば<a href="/wiki/%E5%8D%94%E5%AE%9A%E4%B8%96%E7%95%8C%E6%99%82" title="協定世界時">UTC</a>）。</li> <li id="footer-info-copyright">テキストは<a rel="nofollow" class="external text" href="https://creativecommons.org/licenses/by-sa/4.0/deed.ja">クリエイティブ・コモンズ表示-継承ライセンス</a>のもとで利用できます。追加の条件が適用される場合があります。詳細については<a class="external text" href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Terms_of_Use">利用規約</a>を参照してください。</li> </ul> <ul id="footer-places"> <li id="footer-places-privacy"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy/ja">プライバシー・ポリシー</a></li> <li id="footer-places-about"><a href="/wiki/Wikipedia:%E3%82%A6%E3%82%A3%E3%82%AD%E3%83%9A%E3%83%87%E3%82%A3%E3%82%A2%E3%81%AB%E3%81%A4%E3%81%84%E3%81%A6">ウィキペディアについて</a></li> <li id="footer-places-disclaimers"><a href="/wiki/Wikipedia:%E5%85%8D%E8%B2%AC%E4%BA%8B%E9%A0%85">免責事項</a></li> <li id="footer-places-wm-codeofconduct"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Universal_Code_of_Conduct">行動規範</a></li> <li id="footer-places-developers"><a href="https://developer.wikimedia.org">開発者</a></li> <li id="footer-places-statslink"><a href="https://stats.wikimedia.org/#/ja.wikipedia.org">統計</a></li> <li id="footer-places-cookiestatement"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Cookie_statement">Cookieに関する声明</a></li> <li id="footer-places-mobileview"><a href="//ja.m.wikipedia.org/w/index.php?title=%E5%8D%8A%E5%BE%84&mobileaction=toggle_view_mobile" class="noprint stopMobileRedirectToggle">モバイルビュー</a></li> </ul> <ul id="footer-icons" class="noprint"> <li id="footer-copyrightico"><a href="https://wikimediafoundation.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/static/images/footer/wikimedia-button.svg" width="84" height="29" alt="Wikimedia Foundation" loading="lazy"></a></li> <li id="footer-poweredbyico"><a href="https://www.mediawiki.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/w/resources/assets/poweredby_mediawiki.svg" alt="Powered by MediaWiki" width="88" height="31" loading="lazy"></a></li> </ul> </footer> </div> </div> </div> <div class="vector-settings" id="p-dock-bottom"> <ul></ul> </div><script>(RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgHostname":"mw-web.codfw.main-f69cdc8f6-r5tzf","wgBackendResponseTime":142,"wgPageParseReport":{"limitreport":{"cputime":"0.428","walltime":"0.648","ppvisitednodes":{"value":8441,"limit":1000000},"postexpandincludesize":{"value":66585,"limit":2097152},"templateargumentsize":{"value":17242,"limit":2097152},"expansiondepth":{"value":40,"limit":100},"expensivefunctioncount":{"value":9,"limit":500},"unstrip-depth":{"value":1,"limit":20},"unstrip-size":{"value":25904,"limit":5000000},"entityaccesscount":{"value":1,"limit":400},"timingprofile":["100.00% 530.721 1 -total"," 35.29% 187.279 2 Template:Reflist"," 15.55% 82.531 7 Template:Citation/identifier"," 14.08% 74.746 1 Template:Cite"," 13.77% 73.080 6 Template:ISBN2"," 13.67% 72.527 4 Template:Citation/core"," 13.24% 70.260 1 Template:Citation/core-ja-jp"," 11.36% 60.311 1 Template:Wikidata_property"," 11.10% 58.891 1 Template:MathWorld"," 11.01% 58.439 1 Template:Sister"]},"scribunto":{"limitreport-timeusage":{"value":"0.130","limit":"10.000"},"limitreport-memusage":{"value":4936242,"limit":52428800}},"cachereport":{"origin":"mw-web.codfw.main-74dc4d995d-cs85m","timestamp":"20241103143139","ttl":2592000,"transientcontent":false}}});});</script> <script type="application/ld+json">{"@context":"https:\/\/schema.org","@type":"Article","name":"\u534a\u5f84","url":"https:\/\/ja.wikipedia.org\/wiki\/%E5%8D%8A%E5%BE%84","sameAs":"http:\/\/www.wikidata.org\/entity\/Q173817","mainEntity":"http:\/\/www.wikidata.org\/entity\/Q173817","author":{"@type":"Organization","name":"\u30a6\u30a3\u30ad\u30e1\u30c7\u30a3\u30a2\u30d7\u30ed\u30b8\u30a7\u30af\u30c8\u3078\u306e\u8ca2\u732e\u8005"},"publisher":{"@type":"Organization","name":"\u30a6\u30a3\u30ad\u30e1\u30c7\u30a3\u30a2\u8ca1\u56e3","logo":{"@type":"ImageObject","url":"https:\/\/www.wikimedia.org\/static\/images\/wmf-hor-googpub.png"}},"datePublished":"2003-11-19T06:56:16Z","dateModified":"2022-12-03T03:09:04Z","image":"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/c\/c3\/%E7%90%83%E3%81%AE%E5%8D%8A%E5%BE%84.png","headline":"\u4e00\u822c\u7684\u306b\u3001\u5186\u3084\u7403\u306e\u76f4\u5f84\u306e\u534a\u5206\u304a\u3088\u3073\u305d\u306e\u9577\u3055"}</script> </body> </html>