Date: Topic: Similar Polygons (7.4) Warm-up: Solve each proportion 1. Cross multiply 2. 3. 10 10 a = 6 c = 32

Similar Polygons 10 Polygons are similar (~) if they are exactly the same shape and corresponding angles are congruent and corresponding sides are proportional. 14 20 5 7 10 24 12 Polygons are similar if both are true: The corresponding sides are in the same proportion with one another. or or or The corresponding angles are congruent.

The similarity ratio is or or or Find the similarity ratio, then find a, b, and c 4 Corresponding sides are proportional. a 7 c b 15 21 37° The similarity ratio is or or or

c = 37° Find the similarity ratio, then find a, b, and c 4 find a: find b: 5 a 7 c 37° 12 b 15 21 37° find c: Similar polygons corresponding angles are congruent . c = 37°

3 3 x = 8 z = 46° The triangles are similar. Find x, y, and z. 3 The similarity ratio is or 3:4 or .75 9 y 46° 6 find x: find y: 4 12 46° z x 3 3 8 x = 8 find z: Similar polygons corresponding angles are congruent. z = 46°