1. SSS & SAS Congruence Postulates Mrs. McConaughy Geometry1 Daily Warm-Up 1. What two conditions must be met to show congruent polygons?  ___________________________. 2. If MEAT  SHOP what can you determine? 3. Name and illustrate one congruence shortcut for triangles.

2. SSS & SAS Congruence Postulates Mrs. McConaughy Geometry2 Showing Triangles Congruent At the end of this lesson, you should be able to prove two triangles are congruent by using SAS or SSA (ASS). Which one works?

3. SSS & SAS Congruence Postulates Mrs. McConaughy Geometry3 The six different combinations of congruent pairs of three parts are diagrammed below. Side-Side-Side * Angle-Angle-Angle * Side-Angle-Side SSS AAA  CBD Side-Side-Angle Angle-Side-Angle Angle-Angle-Side CBD

4. SSS & SAS Congruence Postulates Mrs. McConaughy Geometry4 SA Side-Angle-Side Postulate If two sides and the included angle of one triangle correspond and are congruent to two sides and the included angle of another triangle, then the two triangles are congruent. ( SAS Postulate) Side-Angle-Side

5. ALERT A note on what it means to be an included angle: SSS & SAS Congruence Postulates Mrs. McConaughy Geometry5 The included angle means the angle between two sides. In other words, the angle is actually formed by the two sides.

6. What about SSA/ASS (Side Side Angle/Angle Side Side)?. SSS & SAS Congruence Postulates Mrs. McConaughy Geometry6 If two triangles have two congruent sides and a congruent non-included angle, then triangles are NOT NECESSARILY congruent

7. In which pair of triangles pictured below could you use the Side Angle Side postulate (SAS) to prove the triangles are congruent? SSS & SAS Congruence Postulates Mrs. McConaughy Geometry7

8. SSS & SAS Congruence Postulates Mrs. McConaughy Geometry8 Showing Two ∆s Congruent Given: WO ≡ NE M is the midpoint of WN and OE Are the two triangles congruent? Explain. Write a congruence statement. W O M E N

9. SSS & SAS Congruence Postulates Mrs. McConaughy Geometry9 Showing Triangles Congruent T E A M Given: TE //AM ∆ MAT  ________ Reason: _________ 1 2

10. SSS & SAS Congruence Postulates Mrs. McConaughy Geometry10 Wrap Up: Final Checks for Understanding 1.What two conditions must be met to determine congruent polygons? 2. Name and illustrate two congruence shortcuts for showing two triangles are congruent. 3. Which two combinations of sides and angles cannot be used to determine congruent triangles