proportional

8 4 2 12 3 9 6 not equal not similar 8 16 1 2 12 24 9 18 equal ABC GHJ

10 20 20 10 80 10 30 11 11 8 25 4 10 8 20 4 10 25 11 SSS Similarity Theorem

∆PQR ~ ∆ZXY x 30 = 42 35 AB QR BC RP x = 36

proportional

B E B E DE BC 32 20 8 5 proportional SAS Similarity Theorem Yes, the top and bottom are similar. If the side length of the top is a, and the bottom is b, then ratio of all the corresponding sides is , and all corresponding angles are congruent. The triangles are similar by SAS or SSS. a b

QR RS = 9 12 3 4 PR TR = 18 24 3 4 proportional congruent vertical SAS Similarity Theorem

LK MK = 28 16 7 4 KJ KL 49 JL LM 56 32 All of the corresponding sides are proportional so the triangles are similar by the SSS Similarity Theorem.