Section 5.9 CPCTC

Corresponding Parts of Congruent Triangles are Congruent

We will begin going over the flow proof problems that I assigned them for homework two days ago.(Yesterday we worked in the lab using GSP to do some flow proofs.

Next, I will lead into Section 5.9 CPCTC.

Okay, students so far we have been proving two triangles congruent using SSS, SAS, ASA, AAS and Hypotenuse Leg Congruence Theorems. Now, once we know the two triangles are congruent, we also know that all the corresonding parts including angles and segments are congruent.

This is known as

CPCTC - Corresponding Parts of Congruent Triangles are Congruent

We will practice proving triangles congruent and then labeling all corresponding angles and sides congruent.

Based on what is given in the above two triangles,

by Side Side Side Congruence.

Now that we know the two triangles are congruent, we can draw some more conclusions about corresponding angles and sides. We can conclude that

.

If the kids understand how to use CPCTC, we will do this two-column proof on the board.

We will do a couple more proofs on the board using CPCTC. I will tell them about us having a quiz tomorrow covering Sections 5.6-5.9. If we have time, we will review some today for the quiz. If not, we wil review for the quiz at the beginning of class tomorrow.