4.2 SSS and SAS Brett Solberg AHS ’11-’12

Warm-up Are the following triangles congruent? Why or why not? Write a congruence statement for the triangles. Do you have any homework questions?

Today’s Agenda 4.2 Activity Applying 2 Postulates Discover 2 new tools to help prove triangles are congruent. Applying 2 Postulates

Activity Get into groups of 3. Send one person up to pick up: A bag 2 different colored pencils A ruler A worksheet DO NOT START UNTIL I TELL YOU TO DO SO.

Activity Wrap-up Return the materials. Return to your seat. Get out your notes.

Side-Side-Side (SSS) Postulate If the three sides of one triangle are congruent to the three sides of another triangle, then the triangles are congruent. triangle ABC congruent triangle A’B’C’

Example Statement Reason AB ≅ BC Given AD ≅ CD BD ≅ BD Reflexive Property Tri ABD ≅ Tri CBD SSS Postulate

Side-Angle-Side (SAS) Postulate If 2 sides and the included angle of one triangle are congruent to two sides and the included angle of another triangle, then the two triangles are congruent.

Example AC ≅ EC Given BC ≅ DC Given ∠ACB ≅ ∠ECD Vertical Angles Tri ABC ≅ Tri EDB SAS Postulate

Included Included is used when referring to the angles and sides of a triangle. BX is included between ∠X and ∠B. ∠N is included between NB and NX

Homework Assignment 4.2 Worksheet Pg. 208 #8-17, 20-25 TURN IN YOUR GROUP WORKSHEET!