<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>1.C: Proportions and Similar Polygons</title>
<meta name="identifier" content="i009aba8f73e8638d52dcc17ec0b05619"/>
<meta name="editing_roles" content="teachers"/>
<meta name="workflow_state" content="active"/>
</head>
<body>
<div id="HS21">
<div class="overview">
<h2>Overview</h2>
<p>The purpose of this lesson is to use properties of similar polygons and proportions to find unknown measures.</p>
<p>This lesson will address the following CCRS Standard(s) for Geometry:</p>
<ul>
<li><em>7.G.1: Solve problems involving scale drawings of geometric figures, including computing actual lengths and areas from a scale drawing and reproducing a scale drawing at a different scale</em></li>
<li><em>8.G.5: Use informal arguments to establish facts about the angle sum and exterior angles of triangles, above the angles created when parallel lines are cut by a transversal, and the angle-angle criterion for similarity of triangles. For example, arrange three copies of the same triangle so that the sum of the three angles appears to form a line, and give an argument in terms of transversals why this is so</em></li>
</ul>
</div>
<div class="directions">
<h2>Directions</h2>
<ol>
<li>Take notes while watching videos below</li>
<li>Go to <a class="external" href="http://wamap.org/" target="_blank">http://wamap.org</a> and log into our course to complete assignment 1.C with 80% or better.</li>
</ol>
</div>
<h3>Watch</h3>
<p><a class="" href="https://youtu.be/ltYXMyzk3DE">Proportions and Similar Polygons [7:11]</a></p>
<h3>Do</h3>
<p>Complete assignment 1.C with 80% or better at <a href="http://wamap.org">http://wamap.org</a></p>
<div class="summary">
<h2>Summary</h2>
<p>In this lesson we have learned:</p>
<ul>
<li>Given the proportion <img class="equation_image" title="\frac{a}{b}=\frac{c}{d}" src="https://sbctc.instructure.com/equation_images/%255Cfrac%257Ba%257D%257Bb%257D%253D%255Cfrac%257Bc%257D%257Bd%257D" alt="LaTeX: \frac{a}{b}=\frac{c}{d}" data-mathml='<math xmlns="http://www.w3.org/1998/Math/MathML">
<mfrac>
<mi>a</mi>
<mi>b</mi>
</mfrac>
<mo>=</mo>
<mfrac>
<mi>c</mi>
<mi>d</mi>
</mfrac>
</math>' data-equation-content="\frac{a}{b}=\frac{c}{d}">, we can solve by multiplying diagonals to get ad = bc.</li>
<li>If to polygons are similar, then corresponding sides are proportional</li>
<li>If two angles of one triangle are congruent to two angles of another triangle, then the triangle's sides are proportional.</li>
</ul>
</div>
</div>
</body>
</html>