1. 1-1a Slide 1 of 2 (over Lesson 9-3)

2. 1-1b Slide 1 of 2 (over Lesson 9-3)

3. You will learn to identify and use the relationships between proportional parts of triangles. Nothing New!

4. In ΔPQR, T S R Q P Are ΔPQR and ΔPST, similar? and intersects the other two sides of ΔPQR.  PST   PQR corresponding angles  P   P ΔPQR ~ ΔPST. Why? (What theorem / postulate?) AA Similarity (Postulate 9-1)

5. Theorem 9-4 If a line is _______ to one side of a triangle, and intersects the other two sides, then the triangle formed is _______ to the original triangle. similar parallel A B C D E If ΔABC ~ ΔADE.

6. T W S V R Complete the proportion: Since, ΔSVW ~ ΔSRT. SV

7. Theorem 9-5 If a line is parallel to one side of a triangle and intersects the other two sides, then it separates the sides into segments of __________________. proportional lengths E D C B A

8. C B H G A 5 3 x + 5 x 4

9. 10 ft 6 ft 4 ft Brace Jacob is a carpenter. Needing to reinforce this roof rafter, he must find the length of the brace. 4 = 10 4 x 10x = 16 x = 1 3 5 ft 4 ft x