1. 7.3 SIMILAR TRIANGLES Brett SolbergAHS‘11-’12

2. Warm-up 1) Find the following: 2) Find x: Are there any HW problems you want to review?

3. Today’s Agenda Proving Triangles Similar Similarity/Congruence Theorems/Postulates Thales Announcements Quiz next class

4. Triangle Congruence vs. Similarity If two triangles are congruent, then… Corresponding angles are congruent Corresponding side lengths are congruent If two triangles are similar, then… Corresponding angles are congruent Corresponding side lengths are proportional

5. Toolbox Triangle Congruence SSS SAS ASA AAS HL isosceles equilateral properties

6. Tools of Triangle Similarity Angle-Angle Similarity Postulate: (aka third angles theorem) If two angles of one triangle are congruent to two angles of another triangle, then the third angles are congruent.

7. Tools of Triangle Similarity SAS If an angle of one triangle is congruent to the angle of another triangle, and the sides containing the angle are proportional, then the triangles are similar. SAS

8. Tools of Triangle Similarity Side-Side-Side If corresponding sides of two triangles are proportional, then the triangles are similar. SSS

9. Example 1 Why are the triangles similar? Write a similarity statement.

10. Example 2 Find x and y. Are the triangles similar? Explain.

11. Math History Thales of Miletos 625 – 547 BC Lived in Greece Philosopher, Mathematician, Astronomer, Historian.

12. Thales in Egypt

13. Thales and the Great Pyramid

14. Thales and Ships

15. Operation Flagpole Pick a partner Complete the Operation Flagpole Worksheet

16. Homework 7.3 Worksheet & pg 385 # 2- 14 even