1. Hypotenuse Leg (HL)

2. Other Possibilities? SSA 30  Will this ever Work?

3. Special Case of SSA Given a right angle, one leg, & the hypotenuse - Does this prove the triangles congruent? S S A

4. Yes – Remember Pythagorean Theorem a 2 + b 2 = c 2 c b a b’ a’ c’

5. a 2 + b 2 = c 2 Because of Pythagorean thm. a must = a’ This gives SSS  5 3 a 3 a’ 5

6. HL  Theorem If the hyp & leg of one right /\ are  to the hyp & leg of another right /\ then the /\ are 

7. Exercise 21 Given: <A  <D AF  DC AC  DF <BFA  <ECD Prove: /\ AFB  /\ DCE A E F B C D 1 3 2 4

8. Exercise 22 Given: <1  <4 AF  DC <A  <D Prove: /\ AFB  /\ DCE A E F B C D 1 3 2 4