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Similar Polygons. Lesson 5-2. Similar Polygons. Definition: Two polygons are similar if: 1. Corresponding angles are congruent. 2. Corresponding sides are in proportion. Two polygons are similar if they have the same shape not necessarily have the same size.
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Similar Polygons Lesson 5-2 Lesson 5-2: Similar Polygons
Similar Polygons Definition: Two polygons are similar if: 1. Corresponding angles are congruent. 2. Corresponding sides are in proportion. Two polygons are similar if they have the same shape not necessarily have the same size. The scale factor is the ratio between a pair of corresponding sides. Scale Factor: Lesson 5-2: Similar Polygons
Naming Similar Polygons When naming similar polygons, the vertices (angles, sides) must be named in the corresponding order. P Q A B D C S R Lesson 5-2: Similar Polygons
A 15 E D x H 20 y 10 5 F B z G C 30 Example- The two polygons are similar. Solve for x, y and z. Step1: Write the proportion of the sides. Step 2: Replace the proportion with values. Step 3: Find the scale factor between the two polygons. Note: The scale factor has the larger quadrilateral in the numerator and the smaller quadrilateral in the denominator. Step 4: Write separate proportions for each missing side and solve. Lesson 5-2: Similar Polygons
B 10 C 5 Y X 7 14 18 9 Z A Example: If ABC ~ZYX, find the scale factor from ABC to ZYX. Scale factor is same as the ratio of the sides. Always put the first polygon mentioned in the numerator. The scale factor from ABC to ZYX is 2/1. ½ What is the scale factor from ZYX to ABC? Lesson 5-2: Similar Polygons