# Unit 5 Lesson 3 Prove Triangles Similar by

Unit 5 Lesson 3 Prove Triangles Similar by SSS~ and SAS~

Side-Side Similarity (SSS~): Two triangles are similar if the 3 corresponding side lengths are proportional A D B C E F

Side-Angle-Side Similarity (SAS~): Two triangles are similar if 2 corresponding sides are proportional and the included angle is congruent A D B C E F

1. Verify that ABC ~ DEF. Find the scale factor of ABC to DEF. ABC: AB = 12, BC = 15, AC = 9 DEF: DE = 8, EF = 10, DF = 6 A 9 12 D 8 B 15 C E Scale Factor: 6 10 F

2. Is either LMN or RST similar to ABC? Explain. ABC ~ RST by SSS~

3. Determine whether the two triangles are similar. If they are similar, write a similarity statement and find the scale factor of Triangle B to Triangle A. L X YES or NO YXZ ~ ______ JLK ______ Scale Factor:

3. Determine whether the two triangles are similar. If they are similar, write a similarity statement and find the scale factor of Triangle B to Triangle A. YES or NO ______ ~ ______ Scale Factor:

4. Determine whether the triangles are similar. If they are similar, state which postulate or theorem that justifies your answer. Show all work! 15 10 4 6 GKH NKM YES or NO SAS ~ Reason: ______

4. Determine whether the triangles are similar. If they are similar, state which postulate or theorem that justifies your answer. Show all work! ABC DEC B E YES or NO AA ~ Reason: ______

4. Determine whether the triangles are similar. If they are similar, state which postulate or theorem that justifies your answer. Show all work! YES or NO Reason: ______

HW Problem LTs 5. 2 Assignment 3 -11, 15, 16, 33 (a & b only) #10 18 15 16. 5 24 20 22 ∆HGJ ~ ∆HFK By SSS~

- Slides: 11