1. Proving RightTriangles Congruent Free powerpoints at http://www.worldofteaching.comhttp://www.worldofteaching.com

2. Two geometric figures with exactly the same size and shape. The Idea of a Congruence A C B DE F

3. How much do you need to know... need to know...... about two triangles to prove that they are congruent?

4. In Lesson 4.2, you learned that if all six pairs of corresponding parts (sides and angles) are congruent, then the triangles are congruent. Corresponding Parts  ABC   DEF B A C E D F 1.AB  DE 2.BC  EF 3.AC  DF 4.  A   D 5.  B   E 6.  C   F

5. Do you need all six ? NO ! SSS SAS ASA AAS

6. Do you need to use these for right triangles ? NO ! HL HA LL LA

7. Right triangle vocabulary Leg hypotenuse leg Since you know the right angles always match you only need two more parts to be congruent.

8. LL : leg - leg

9. LA : leg - angle

10. HA : hypotenuse - angle

11. HL : hypotenuse - leg

12. Name That Postulate (when possible)

13. Let’s Practice Indicate the additional information needed to enable us to apply the specified congruence postulate. For ASA: For SAS:  B   D For AAS: A  F A  F AC  FE

14. HW Indicate the additional information needed to enable us to apply the specified congruence postulate. For LA: For LL: A C B D FE