4.7 Guided Notes – Using CPCTC
I WILL GRADE THIS FOR CORRECTNESS. IT WILL GO IN AS A QUIZ GRADE!! This worksheet
must be done by the end of the class period!!
1. What does CPCTC stand for?
2. Write a short paragraph describing how you could use CPCTC in a proof.
Use the following diagram for numbers 3-7
3. What triangles do you want to prove are congruent in order to prove that BD  FD ?
4. What else do you need to know to prove that the triangles mentioned in part 1 are congruent? Can you
do that with the information that’s given?
5. If no, what two triangles can you prove are congruent with the info given? What could you use to prove
they are congruent (SSS, SAS, ASA, AAS)? If it helps, separate the triangles and redraw them, like:
6. If you prove the two triangles from part 5 are congruent, how will that help you prove the triangles from
part 3 are congruent?
7. Use your plan from parts 3 – 6 to make a formal proof:
Statements
8. Now try a few on your own:
Justifications
Homework #34 – Worksheet 4.7