Rectangle

<!doctype html> <html lang="en"> <head> <meta charset="UTF-8">  <title>Rectangle</title> <meta name="description" content="(Jump to Area of a Rectangle or Perimeter of a Rectangle) ... A rectangle is a four-sided flat shape where every angle is a right angle (90).">  <meta name="keywords" content="math, maths, mathematics, school, homework, education"> <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes"> <meta name="HandheldFriendly" content="true"> <meta name="referrer" content="always"> <link rel="preload" href="../images/style/font-champ-bold.ttf" as="font" type="font/ttf" crossorigin> <link rel="preload" href="../style4.css" as="style"> <link rel="preload" href="../main4.js" as="script"> <link rel="stylesheet" href="../style4.css"> <script src="../main4.js" defer></script> </head> <body id="bodybg"> <div id="stt"></div> <div id="adTop"></div> <header> <div id="hdr"></div> <div id="tran"></div> <div id="adHide"></div> <div id="cookOK"></div> </header> <div class="mid"> <nav> <div id="menuWide" class="menu"></div> <div id="logo"><a href="https://www.mathsisfun.com/"><img src="../images/style/logo.svg" alt="Math is Fun"></a></div> <div id="themeChg"></div> <div id="search" role="search"></div> <div id="linkto"></div> <div id="menuSlim" class="menu"></div> <div id="menuTiny" class="menu"></div> </nav> <div id="extra"></div> <article id="content" role="main">  <h1 class="center">Rectangle</h1> <p class="center"><i>(Jump to <a href="#Area">Area of a Rectangle</a> or <a href="#Perimeter">Perimeter of a Rectangle</a>)</i></p> <p class="center">A rectangle is a four-sided flat shape where every angle is a <a href="../rightangle.html">right angle</a> (90°).</p> <p class="center"><img src="images/rectangle-angles.svg" alt="Rectangle" height="113" width="158"><i><br> the little squares in each corner mean "right angle"</i></p> <table style="border-spacing: 5px;" border="0"> <tr> <td><img src="../images/style/right-arrow.gif" alt="right arrow" height="46" width="46"></td> <td>Each internal angle is 90°</td> </tr> <tr> <td><img src="../images/style/right-arrow.gif" alt="right arrow" height="46" width="46"></td> <td> <p>Opposite sides are <a href="parallel-lines.html">parallel</a> and of equal length (so it is a <a href="parallelogram.html">Parallelogram</a>).</p></td> </tr> </table> <p>Play with a rectangle:</p> <div class="script" style="height: 330px;"> images/geom-quad.js?mode=rectangle</div> <h2 id="Area">Area of a Rectangle</h2> <table style="border: 0; margin:auto;"> <tr> <td><img src="images/rectangle-area.svg" alt="rectangle area" height="91" width="145"></td> <td> </td> <td> <p class="center larger">Area = a × b</p></td> </tr> </table> <div class="example"> <h3>Example: A rectangle is 6 m wide and 3 m high, what is its Area?</h3> <div class="tbl"> <div class="row"><span class="lt">Area</span><span class="rtlt">= 6 m × 3 m</span></div> <div class="row"><span class="lt"> </span><span class="rtlt">= <b>18 m<sup>2</sup></b></span></div> </div> </div> <h2 id="Perimeter">Perimeter of a Rectangle</h2> <p>The Perimeter is the distance around the edges.</p> <table style="border: 0; margin:auto;"> <tr> <td><img src="images/rectangle-perim.svg" alt="rectangle perimeter" height="95" width="150"></td> <td> </td> <td> <p>The Perimeter is <b>2 times (a + b)</b>:</p> <p class="center larger">Perimeter = 2(a+b)</p></td> </tr> </table> <div class="example"> <h3>Example: A <span class="center">rectangle</span> is 12 cm long and 5 cm tall, what is its Perimeter?</h3> <div class="tbl"> <div class="row"><span class="lt">Perimeter </span><span class="rtlt">= 2 × (12 cm + 5 cm)</span></div> <div class="row"><span class="lt"> </span><span class="rtlt">= 2 × 17 cm</span></div> <div class="row"><span class="lt"> </span><span class="rtlt">= <b>34 cm</b></span></div> </div> </div> <h2>Diagonals of a Rectangle</h2> <table style="border: 0;"> <tr> <td><img src="images/rectangle-diags.svg" alt="rectangle diagonals" height="56" width="114"></td> <td> </td> <td> <p>A <span class="center">rectangle</span> has two diagonals, they are equal in length and intersect in the middle.</p></td> </tr> </table> <table style="border: 0; margin:auto;"> <tr> <td><img src="images/rectangle-diag.svg" alt="rectangle diagonal calculation" height="89" width="148"></td> <td> </td> <td> <p>A diagonal's length is the <b> square root of (a squared + b squared)</b>:</p> <p class="center larger">Diagonal "d" = √(a<sup>2</sup> + b<sup>2</sup>)</p></td> </tr> </table> <div class="example"> <h3>Example: A rectangle is 12 cm wide, and 5 cm tall, what is the length of a diagonal?</h3> <p style="float:left; margin: 0 10px 5px 0;"><img src="images/rectangle-diag-ex.svg" alt="rectangle diagonal example" height="99" width="149"></p> <div class="tbl"> <div class="row"><span class="lt">d</span><span class="rtlt">= √(12<sup>2</sup> + 5<sup>2</sup>)</span></div> <div class="row"><span class="lt"></span><span class="rtlt">= √(144 + 25)</span></div> <div class="row"><span class="lt"></span><span class="rtlt">= √169</span></div> <div class="row"><span class="lt"></span><span class="rtlt">= <b>13 cm</b></span></div> </div> </div> <p style="float:right; margin: 0 0 5px 10px;"><img src="../numbers/images/golden-rectangle.svg" alt="Golden rectangle" height="155" width="188"></p> <h2>Golden Rectangle</h2> <p>There is also a special rectangle called the <a href="../numbers/golden-ratio.html">Golden <span class="center">Rectangle</span></a>:</p> <div style="clear:both"></div> <div class="questions">9091, 9092, 9093, 9094, 9095, 9096, 9097, 9098, 9099, 9100</div> <div class="related"> <a href="rectangle-calc.html">Rectangle Calculator</a> <a href="../quadrilaterals.html">Quadrilaterals</a> <a href="index.html">Geometry Index</a> </div>  </article> <div id="adend" class="centerfull noprint"></div> <footer id="footer" class="centerfull noprint"></footer> <div id="copyrt">Copyright © 2024 Rod Pierce</div> </div> </body>  </html>

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Rectangle