e39465ad2f
new file: Files/flashplayer_32_sa.exe
new file: favicon.ico
new file: globe.gif
new file: imgs/download.png
new file: imgs/zuck.jpg
new file: index.html
new file: other.ico
new file: script.js
new file: site.webmanifest
new file: sitemap.html
new file: styles/backround.css
new file: styles/border.css
new file: styles/fonts/Titillium_Web/OFL.txt
new file: styles/fonts/Titillium_Web/TitilliumWeb-Black.ttf
new file: styles/fonts/Titillium_Web/TitilliumWeb-Bold.ttf
new file: styles/fonts/Titillium_Web/TitilliumWeb-BoldItalic.ttf
new file: styles/fonts/Titillium_Web/TitilliumWeb-ExtraLight.ttf
new file: styles/fonts/Titillium_Web/TitilliumWeb-ExtraLightItalic.ttf
new file: styles/fonts/Titillium_Web/TitilliumWeb-Italic.ttf
new file: styles/fonts/Titillium_Web/TitilliumWeb-Light.ttf
new file: styles/fonts/Titillium_Web/TitilliumWeb-LightItalic.ttf
new file: styles/fonts/Titillium_Web/TitilliumWeb-Regular.ttf
new file: styles/fonts/Titillium_Web/TitilliumWeb-SemiBold.ttf
new file: styles/fonts/Titillium_Web/TitilliumWeb-SemiBoldItalic.ttf
new file: styles/fonts/webfontkit-20221027-163353/generator_config.txt
new file: styles/fonts/webfontkit-20221027-163353/specimen_files/grid_12-825-55-15.css
new file: styles/fonts/webfontkit-20221027-163353/specimen_files/specimen_stylesheet.css
new file: styles/fonts/webfontkit-20221027-163353/stylesheet.css
new file: styles/fonts/webfontkit-20221027-163353/titilliumweb-extralight-demo.html
new file: styles/fonts/webfontkit-20221027-163353/titilliumweb-extralight-webfont.woff
new file: styles/fonts/webfontkit-20221027-163353/titilliumweb-extralight-webfont.woff2
new file: styles/fonts/webfontkit-20221027-165950/generator_config.txt
new file: styles/fonts/webfontkit-20221027-165950/specimen_files/grid_12-825-55-15.css
new file: styles/fonts/webfontkit-20221027-165950/specimen_files/specimen_stylesheet.css
new file: styles/fonts/webfontkit-20221027-165950/stylesheet.css
new file: styles/fonts/webfontkit-20221027-165950/titilliumweb-bold-demo.html
new file: styles/fonts/webfontkit-20221027-165950/titilliumweb-bold-webfont.woff
new file: styles/fonts/webfontkit-20221027-165950/titilliumweb-bold-webfont.woff2
new file: styles/style.css
new file: tools/2048/.gitignore
new file: tools/2048/.jshintrc
new file: tools/2048/CONTRIBUTING.md
new file: tools/2048/LICENSE.txt
new file: tools/2048/README.md
new file: tools/2048/Rakefile
new file: tools/2048/favicon.ico
new file: tools/2048/index.html
new file: tools/2048/js/animframe_polyfill.js
new file: tools/2048/js/application.js
new file: tools/2048/js/bind_polyfill.js
new file: tools/2048/js/classlist_polyfill.js
new file: tools/2048/js/game_manager.js
new file: tools/2048/js/grid.js
new file: tools/2048/js/html_actuator.js
new file: tools/2048/js/keyboard_input_manager.js
new file: tools/2048/js/local_storage_manager.js
new file: tools/2048/js/tile.js
new file: tools/2048/meta/apple-touch-icon.png
new file: tools/webretro/cores/neocd_libretro.js
new file: tools/webretro/cores/neocd_libretro.wasm
new file: tools/webretro/cores/nestopia_libretro.js
new file: tools/webretro/cores/nestopia_libretro.wasm
new file: tools/webretro/cores/o2em_libretro.js
new file: tools/webretro/cores/o2em_libretro.wasm
new file: tools/webretro/cores/opera_libretro.js
new file: tools/webretro/cores/opera_libretro.wasm
130 lines
4.7 KiB
HTML
130 lines
4.7 KiB
HTML
<!DOCTYPE html>
|
||
<html lang="en"><!-- #BeginTemplate "/Templates/Main.dwt" --><!-- DW6 -->
|
||
|
||
<!-- Mirrored from www.mathsisfun.com/proof180deg.html by HTTrack Website Copier/3.x [XR&CO'2014], Sat, 29 Oct 2022 00:43:17 GMT -->
|
||
<head>
|
||
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
|
||
|
||
<!-- #BeginEditable "doctitle" -->
|
||
<title>Triangles Contain 180 Degrees</title>
|
||
|
||
<!-- #EndEditable -->
|
||
<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="defer"></script>
|
||
<!-- Global site tag (gtag.js) - Google Analytics -->
|
||
<script async="" src="https://www.googletagmanager.com/gtag/js?id=UA-29771508-1"></script>
|
||
<script>
|
||
window.dataLayer = window.dataLayer || [];
|
||
function gtag(){dataLayer.push(arguments);}
|
||
gtag('js', new Date());
|
||
gtag('config', 'UA-29771508-1');
|
||
</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="index.html"><img src="images/style/logo.svg" alt="Math is Fun"></a></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">
|
||
|
||
<!-- #BeginEditable "Body" -->
|
||
|
||
|
||
<h1 class="center">Triangles Contain 180°</h1>
|
||
|
||
<table style="border: 0; margin:auto;">
|
||
<tbody>
|
||
<tr>
|
||
<td><img src="algebra/images/triangle-sides-angles.svg" alt="Triangle with angles A,B,C" height="131" width="220"></td>
|
||
<td>
|
||
|
||
<h3>In a triangle, the three interior angles always add to 180°:</h3>
|
||
<p class="center large">A + B + C = 180°</p></td>
|
||
</tr>
|
||
</tbody></table>
|
||
<p>Try it yourself (drag the points):</p>
|
||
<div class="script" style="height: 360px;">
|
||
geometry/images/triangle.js?mode=angles
|
||
</div>
|
||
<p>We can use that fact to find a missing angle in a triangle:</p>
|
||
<div class="example">
|
||
|
||
<h3>Example: Find the Missing Angle "C"</h3>
|
||
<p class="center"><img src="algebra/images/triangle-missing-angle.svg" alt="Triangle Missing Angle" height="144" width="162"></p>
|
||
<div class="tbl">
|
||
<div class="row"><span class="left">Start With:</span><span class="right"><span class="larger">A + B + C = 180°</span></span></div>
|
||
<div class="row"><span class="left">Fill in what we know:</span><span class="right"><span class="larger">38° + 85° + C = 180°</span></span></div>
|
||
<div class="row"><span class="left">Rearrange</span><span class="right"><span class="larger"> C = 180° − 38° − 85°</span></span></div>
|
||
<div class="row"><span class="left">Calculate:</span><span class="right"><span class="larger">C = 57°</span></span></div>
|
||
</div>
|
||
</div>
|
||
|
||
|
||
<h2>Proof</h2>
|
||
|
||
<p>This is a proof that the angles in a triangle equal 180°:</p><br>
|
||
<div class="center"><img src="algebra/images/triangle-180-proof.svg" alt="Proof the angles in a triangle add to 180" height="111" width="316"> </div>
|
||
<p class="center large">The top
|
||
line (that touches the top of the triangle) is<br>
|
||
running parallel
|
||
to the base of the triangle.</p>
|
||
<p class="large">Notice that:</p>
|
||
<ul>
|
||
<li>angles <span class="large">A</span> are the
|
||
same</li>
|
||
<li>angles <span class="large">B</span> are the same</li>
|
||
</ul>
|
||
<p class="large">And you can see that <span class="larger">A + C + B</span> rotates from one side of the straight line to the other, or a full <b>180°</b></p>
|
||
<p> </p>
|
||
<div class="questions">732, 1518, 733, 1519, 2139, 2140, 3938, 3939, 2141, 2142</div>
|
||
|
||
<div class="related">
|
||
<a href="pythagoras.html">Pythagoras' Theorem</a>
|
||
<a href="right_angle_triangle.html">Right Angled triangles</a>
|
||
<a href="triangle.html">Triangles</a>
|
||
<a href="algebra/trigonometry-index.html">Trigonometry Index</a>
|
||
</div>
|
||
<!-- #EndEditable -->
|
||
|
||
</article>
|
||
|
||
<div id="adend" class="centerfull noprint"></div>
|
||
<footer id="footer" class="centerfull noprint"></footer>
|
||
<div id="copyrt">Copyright © 2021 MathsIsFun.com</div>
|
||
|
||
</div>
|
||
|
||
|
||
|
||
</body><!-- #EndTemplate -->
|
||
<!-- Mirrored from www.mathsisfun.com/proof180deg.html by HTTrack Website Copier/3.x [XR&CO'2014], Sat, 29 Oct 2022 00:43:17 GMT -->
|
||
</html> |