1. 8.5 Proving Triangles are Similar

2. Side-Side-Side (SSS) Similarity Theorem If the lengths of the corresponding sides of two triangles are proportional, then the triangles are similar. If AB = BC = CA PQ QR RP, then, ΔABC ~ΔPQR A B C P Q R

3. Exercise Determine which two of the three given triangles are similar. Find the scale factor for the pair. K J L 69 12 4 N M P 8 6 R Q S 610 14

4. Which triangles are similar to ΔABC? Explain. A B C 46 8 J K L 2.5 3.75 5.3 M N P 2 3 4

5. Solve for h. A B C D E 12 10 60 h

6. SAS Similarity Theorem X Y Z M N O ) ) then ΔXYZ ~ ΔMNO

7. Determine whether the triangles are similar. If they are, write a similarity statement and solve for the variable. A C B D 8 10 12 15 p ) ) Yes, ΔABC ~ ΔBDC DIVIDE BY 4 DIVIDE BY 5 2p = 3(12) 2p=36 p=18

8. Prove Triangles Similar by AA Triangle Similarity Two triangles are similar if two pairs of corresponding angles are congruent. In other words, you do not need to know the measures of the sides or the third pair of angles.

9. Prove Triangles Similar by AA Example 1: Determine whether the triangles are similar. If they are, write a similarity statement, explain your reasoning.

10. Prove Triangles Similar by AA Example 2: Determine whether the triangles are similar. If they are, write a similarity statement, explain your reasoning.

11. Prove Triangles Similar by AA Example 3: Show that the two triangles are similar. a. Triangle ABE and Triangle ACD b. Triangle SVR and Triangle UVT

12. Prove Triangles Similar by AA Example 5: A school building casts a shadow that is 26 feet long. At the same time a student standing nearby, who is 71 inches tall, casts a shadow that is 48 inches long. How tall is the building to the nearest foot?