4 7 Triangle Congruence CPCTC Remember SSS SAS

4 -7 Triangle Congruence: CPCTC Remember! • SSS , SAS , ASA , AAS , and HL use corresponding parts to prove triangles congruent. • CPCTC uses congruent triangles to prove corresponding parts congruent. • Prove the triangles are congruent FIRST: use CPCTC LAST. Holt Mc. Dougal Geometry

4 -7 Triangle Congruence: CPCTC Example 1 Given: YW bisects XZ, XY YZ. Prove: XYW ZYW ZW Z Holt Mc. Dougal Geometry

4 -7 Triangle Congruence: CPCTC Example 2 Given: PR bisects QPS and QRS. Prove: PQ PS PR bisects QPS Given QPR SPR Def. of bisector PR bisects QRS RP Reflexive Property of QRP SRP ∆PQR ∆PSR Def. of bisector ASA PQ PS CPCTC Holt Mc. Dougal Geometry Given

4 -7 Triangle Congruence: CPCTC Example 3 Given: A(2, 3), B(5, -1), C(1, 0) D(-4, -1), E(0, 2), F(-1, -2) Prove: A D Statements Reasons 1. A(2, 3), B(5, -1), C(1, 0) D(-4, -1), E(0, 2), F(-1, -2) 1. 2. AB = BC = AC = 2. DE = EF = DF = 3. Definition of Congruence 4. 5. Holt Mc. Dougal Geometry

4 -7 Triangle Congruence: CPCTC Your Turn! Holt Mc. Dougal Geometry Workbook pg 171 #2

4 -7 Triangle Congruence: CPCTC 4 – 5, 4 – 6, 4 – 7 Assignment from Textbook • pg 254 #7, 13 • Pg 264 – 265 #6, 13 • pg 270 – 271 #3, 8 (Honors also do #12) • Use the template to fill in all problems except pg 270 #12 as flowchart proofs • Honors: do pg 270 #12 as a two-column proof on a separate piece of paper. • Must write down the whole proof, not just the missing blanks, to get full credit. Holt Mc. Dougal Geometry