Benchmark 37 I can identify two triangles as similar using SSS, SAS, or AA triangle proportionality theorem.

Review Similar figures must have: _________ angles. ___________ sides. Congruent Proportionate

Angle-Angle Similarity Postulate If two <‘s of a Δ are  to two <‘s of another Δ, then the Δ’s are ~. A Z Y XC B If <A  <X and<C  <Z, then ΔABC~ΔXYZ

Are the triangles similar? If so, write a similarity statement. 39  72  41  No 61  60  59  60  Yes A D C B F E R Z Y X T S ΔRST  ΔXYZ

Side-Angle-Side Similarity Thm. If an < of one Δ is  to an < of another Δ, and the sides including the <‘s are proportionate, then the Δ’s are ~. A F E D C B If <A  <D and AB DE AC DF = Then ΔABC~ΔDEF.

Side-Side-Side Similarity Thm. If all corresponding sides of two Δ’s are in proportion, then the Δ’s are ~. A F E D C B If AB DE AC DF = Then ΔABC~ΔDEF. BC EF =