5.7 Vocabulary CPCTC CPCTC is an abbreviation for the phrase “Corresponding Parts of Congruent Triangles are Congruent.” It can be used as a justification in a proof after you have proven two triangles congruent.
SSS, SAS, ASA, AAS, and HL use corresponding parts to prove triangles congruent. CPCTC uses congruent triangles to prove corresponding parts congruent. Use CPCTC AFTER congruent triangles. Remember!
Example 1: Proving Corresponding Parts Congruent Z Given: YW bisects XZ, XY YZ. Prove: XYW ZYW
Check It Out! Example 2 Prove: PQ PS Given: PR bisects QPS and QRS.
Example 3: Using CPCTC in a Proof Prove: MN || OP Given: NO || MP, N P
Example 4: A and B are on the edges of a ravine. What is AB?
Example 5: ∆RST ∆LMP. ST = 2x + 10, TR = 3x, MP = x + 30, LM = 2x + 5 find PL
Lesson Quiz: Part I 1. Given: Isosceles ∆PQR, base QR, PA PB Prove: AR BQ
Lesson Quiz: Part II 2. Given: X is the midpoint of AC . 1 2 Prove: X is the midpoint of BD.
To prove Midpoint: To prove Bisector: To prove Isosceles: