1.C: Proportions and Similar Polygons
- Page ID
- 31436
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Overview
The purpose of this lesson is to use properties of similar polygons and proportions to find unknown measures.
This lesson will address the following CCRS Standard(s) for Geometry:
- 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
- 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
Directions
- Take notes while watching videos below
- Go to http://wamap.org and log into our course to complete assignment 1.C with 80% or better.
Do
Complete assignment 1.C with 80% or better at http://wamap.org
Summary
In this lesson we have learned:
- Given the proportion
, we can solve by multiplying diagonals to get ad = bc.
- If to polygons are similar, then corresponding sides are proportional
- If two angles of one triangle are congruent to two angles of another triangle, then the triangle's sides are proportional.