1. Proving Triangles Similar Related Topic
Remember we had to prove triangles congruent? Proving triangles similar is similar to proving triangles congruent but different
The theorems to prove triangles similar are different

2. Postulate 7.1 Angle-Angle similarity (AA~) Postulate
If two angles of one triangle are congruent to two angles of another triangle, then the triangles are similar P T R S L M

3. Theorem 7.1 Side-Angle-Side Similarity (SAS~) Theorem
If an angle of one triangle is congruent to an angle of a second triangle, and the sides including the two angles are proportional, then the triangles are similar
Examples:
Notice the difference

4. Theorem 7.2 Side-Side-Side (SSS~) Theorem
If the corresponding sides of two triangles are proportional, then the triangles are similar
Examples:

5. Are the triangles similar? Why? Write the similarity statementV S 45 45 R B

6. Are the triangles similar? Why? Write the similarity statementP X 8 6 Z Q R Y 4 3

7. If the triangles are similar, find DE12 10 B 24 D C 16 18 E

8. Vocabulary
Indirect measurement – You use similar triangles and measurements to find distances that are difficult to measure directly

9. Example of indirect measurement