Geometry Section 4.4

Geometry Section 4.4

Using Corresponding parts of Congruent triangles
(CPCTC)

You will have 10 - 20 seconds to choose the reason for these next 7 slides.

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Think Fast
Congruent or Not Congruent?

Multiple Choice

Which triangle congruence postulate proves these two triangles are congruent?

• SSS

• SAS

• ASA

• AAS

• HL

Multiple Choice

Which triangle congruence postulate proves these two triangles are congruent?

• SSS

• SAS

• ASA

• AAS

• HL

Multiple Choice

Which triangle congruence postulate proves these two triangles are congruent?

• SSS

• SAS

• ASA

• AAS

• HL

Multiple Choice

Are these triangles congruent? If so, which postulate proves they are.

• Yes;

  ASA

• Yes;

  HL

• Not Congruent

• Yes;

  SA

Multiple Choice

Are these triangles congruent? If so, which postulate proves they are.

• Yes;

  SSA

• Yes;

  HL

• Not Congruent

• Yes;

  SAS

Multiple Choice

Are these triangles congruent? If so, which postulate proves they are.

• Yes;

  SSS

• Yes;

  SS

• Not Congruent

• Yes;

  SAS

Multiple Choice

Are these triangles congruent? If so, which postulate proves they are.

• Yes;

  AAA

• Yes;

  AA

• Not Congruent

• Yes;

  SSS

Draw

Mark the triangle with congruent symbols on everything you know to be congruent.

We can prove the triangles congruent.

Now that we know which parts are congruent.

Reorder

Where should we start? Reorder the following steps.

• Use the given info to mark the parts of the diagram that are congruent.

• Mark the diagram with anything you know, like shared sides or vertical angles congruent.

• Use SSS, SAS, ASA, or AAS to prove the two triangles are congruent.

• Use CPCTC to prove corresponding parts congruent.

• Use alternate interior angles or corresponding angles to prove the lines parallel.

1

2

3

4

5

• 1
• 2
• 3
• 4
• 5

Multiple Choice

Are the triangles congruent?

• Yes by SSS

• Yes by SAS

• Yes, by ASA

• Yes, by AAS

• No they are not congruent

Multiple Choice

Now that we've proven the angles A and B are congruent, what can we say about segments AD and BC?

• They have to be parallel because alternate interior angles are congruent.

• The have to be congruent because of CPCTC

• They might be congruent

• They are perpendicular

Multiple Choice

Are the triangles congruent?

• Yes by SSS

• Yes by SAS

• Yes, by ASA

• Yes, by AAS

• No they are not congruent

Multiple Choice

Now that we've proven the triangles congruent what do we know about angles A and B?

• They have to be congruent because they are alternate interior angles.

• The have to be congruent because of CPCTC

• They might be congruent

• They are vertical angles.

Multiple Choice

How do you prove the angles congruent?

• SSS and then CPCTC

• SAS and then CPCTC

• ASA and then CPCTC

• AAS and then CPCTC

• No they are not congruent

Multiple Choice

How do you prove the angle MTR and angle NTR congruent?

• SSS and then CPCTC

• SAS and then CPCTC

• ASA and then CPCTC

• AAS and then CPCTC

• No they are not congruent

​Homework

​Practice Sheet 4.4 Google Classroom