1. BASIC GEOMETRY Section 7.3: Triangle Similarity: AA, SSS, & SAS

2. Proving Triangles are Similar
AA ~ Thm: If two angles of one triangle are congruent to two angles in another triangle, then the triangles are similar.

3. SSS ~ Thm: If the 3 sides of one triangle are proportional to 3 sides of another triangle, then the triangles are ~.

4. SAS ~ Thm: If two sides of one triangle are proportional to two sides of another and the included angles are congruent, then the triangles are ~.

5. Proofs
These 3 Thms are used the same as the congruent triangles ones in proofs.
Properties of Similarity

6. Example 1: Explain why the triangles are similar and write a similarity statement.

7. Example 2: Verify that the triangles are similar.
A) ∆PQR & ∆STU B) ∆DEF & ∆HJK

8. Example 3: Explain why ∆ABE ∼ ∆ACD, and then find CD.

9. Example 4: The photo shows a gable roof. AC // FG
Example 4: The photo shows a gable roof. AC // FG. Find BA to the nearest tenth.

10. Assignment #3
Page 474 #’s 1-6,9,10,34-36,(44)