Polygons whose corresponding angles are congruent and corresponding sides are proportional. The ratio of the lengths of two corresponding sides If the SF > 1 then it's an enlargement. If 1 > SF > 0 then it's a reduction. AB DE = 3 6 1 2

D E F 10 15 2 3 8 12 18 AB DE BC EF CA FD ∠P ≅ ∠X, ∠Q ≅ ∠Y, ∠R ≅ ∠Z PQ XY QR YZ RP ZX =

L M K A J A J congruent 8 14 4 7 12 21 proportional JKLM 4 7

proportional CD RS 13 24 312 26

4/5 15 12 40 x = 15x = 480 x = 32

NK SP MN RS LM QR KL PQ

20 16 5 4 2(20) + 2(25) 90 2l + 2w = P 5 4 72

scale factor

JK 8 + 8 5 + 5 16 10 8 5 8 5 8 5 14 22.4 14 40 72 = 5 9 Scale Factor P∆WXY = (72 + 63 + 81) =120 Scale Factor 16 24 = 2 3 QS = (39) = 26