2. 4.9Prove Triangles Congruent by SAS Side-Angle-Side (SAS) Congruence Postulate If two sides and the included angle of one triangle are congruent to two sides and the included angle of a second triangle, then the two triangles are congruent. S R T V U W

3. 4.9Prove Triangles Congruent by SAS Example 1 Use the SAS Congruence Postulate M N L R S T Solution It is given thatand __________. So, by the ____________________________, SAS Congruence Postulate

4. 4.9Prove Triangles Congruent by SAS Hypotenuse-Leg Congruence Theorem If the hypotenuse and a leg of a right triangle are congruent to the hypotenuse and a leg of a second right triangle, then the two triangles are ___________. congruent B A C E D F

5. 4.9Prove Triangles Congruent by SAS Example 2 Use the HL Congruence Theorem Write a proof. Given: Prove: B A C D E StatementsReasons Given

6. 4.9Prove Triangles Congruent by SAS Example 2 Use the HL Congruence Theorem Write a proof. Given: Prove: B A C D E StatementsReasons right angles right triangles right triangle

7. 4.9Prove Triangles Congruent by SAS Example 2 Use the HL Congruence Theorem Write a proof. Given: Prove: B A C D E StatementsReasons Given HL Congruence Theorem

8. 4.9Prove Triangles Congruent by SAS Checkpoint. Complete the following exercises. 1.Decide whether enough information is given to prove ABC LMN using the SAS Congruence Postulate. A B C N M L Sides: Included angle: Therefore there is enough information

9. 4.9Prove Triangles Congruent by SAS Checkpoint. Complete the following exercises. 2.Write a proof. P S Q R Given: Prove: StatementsReasons Given Definition of perp. lines Definition of a right triangle

10. 4.9Prove Triangles Congruent by SAS Checkpoint. Complete the following exercises. 2.Write a proof. P S Q R Given: Prove: StatementsReasons Reflexive Property of Cong. HL Congruence Theorem

11. 4.9Prove Triangles Congruent by SAS Pg. 262, 4.9 #1-16