1. Proving Parts of Triangles using CPCTC
Section 4.3 cont.

2. Proof Format
When using CPCTC to prove that corresponding parts of a triangle are congruent, we use the same general format:
Determine the 3 pieces of congruency based on the given information and the diagram
Determine what the two congruent triangles are and the method of congruence
Use CPCTC to prove the corresponding parts.

3. Complete the following proof:
Statements
Reasons
DF bisects <EDG
DE = DG
2. <1 = <2
3. DF = DF
4. ∆ = ∆ 5.

4. Complete the following proof:
Statements
Reasons
1. PR=SR; PQ=SQ
1. Given
2. QR=QR
2. Reflexive
3. ∆PQR= ∆SQR
3. SSS Postulate
4. <P=<S
4. CPCTC

5. Complete the following proof:
Statements
Reasons
1. C is the midpoint of AD; <A=<D
1. Given
2. AC=CD
2. Def. of a Midpt.
3. <ACB=<DCE
3. Vertical Angles
4. ∆ABC= ∆DEC
4. ASA Postulate
5. BC=EC
5. CPCTC

6. Complete the following proof:
Statements
Reasons
1. WY is perp. To XZ; XY=YZ
1. Given
2. <XYW=<ZYW
2. If 2 lines are perp. Then they form = adj. <s
3. WY=WY
3. Reflexive
4. ∆XYW= ∆ZYW
4. SAS Postulate
5. <X=<Z
5. CPCTC