Perimeter and Area of Similar Figures Sec 5. 3-B pg. 299 - 302

Similar Figures A B C Z 49 90 41 3 4 5 10 8 6 X Y Corresponding Sides – AB and XY, BC and YZ, and AC and XZ are sides that are in the same relative position. Corresponding sides are in proportion. Corresponding Angles - A and X, B and Y and C and  Z are angles that are in the same relative position. Corresponding angles are congruent.

Similar Figures – Find Perimeter B C Z 3 6 𝐴𝐵 𝑋𝑌 = 6 3 , so X Y 6 3 = 𝑃 𝐴𝐵𝐶 𝑃 𝑋𝑌𝑍 6 3 = 𝑃 𝐴𝐵𝐶 12 Given the perimeter of Triangle XYZ is 12, what is the perimeter of Triangle ABC? Perimeters of similar figures are proportional 3PABC = (6)(12) 3 𝑃 𝐴𝐵𝐶 3 = 72 3 PABC = 24

GIVEN SIMILAR FIGURES, find area. Pentagon ABCDE is similar to Pentagon PQRST. Find the area of Pentagon ABCDE if the area of Pentagon PQRST is 20 square inches. P A 𝐴 𝐴𝐵𝐶𝐷𝐸 = 𝐴 𝑃𝑄𝑅𝑆𝑇 ∗ 𝑆𝑐𝑎𝑙𝑒 𝐹𝑎𝑐𝑡𝑜𝑟 2 2 6 T Q 𝐴 𝐴𝐵𝐶𝐷𝐸 = 20 in.2 * 9 B E S R 𝐴 𝐴𝐵𝐶𝐷𝐸 = 180 in.2 Areas of similar figures are proportional to the square of the scale factor. D C 6 2 = 3 1 32 = 9