4-2 Triangle Congruence by SSS and SAS

Objective: to prove two triangles congruent using the SSS and SAS Postulates

Remember: 4.1 Triangle Congruence

If you know 3 pairs of Corresponding Angles are congruent and 3 pairs of Corresponding Sides are Congruent, you knew that the triangles were congruent.

Side Side Side Postulate

All we need is to show 3 pairs of Corresponding Sides are congruent in order to prove Triangle Congruence.

Let’s look at a couple of two-column proofs that utilize the SSS Postulate.

Ex 1:Using SSS

Ex 1B:Try Another Proof!

IncludedWhat does it mean to be included? Like you

were included in an event or batteries are included?

The word Included can also used when referring to the sides and angles of a Triangle.

SAS Postulate

Ex 2: Using SAS

Ex 2B: Using SAS

Ex 3: Are the Triangles Congruent?

Ex 3B: Are the Triangles Congruent?

Apply: Are these Triangles Congruent?

If congruent say why, if not explain what else you would need to know to prove them congruent by SSS or SAS.

Apply: Are these Triangles Congruent?

If congruent say why, if not explain what else you would need to know to prove them congruent by SSS or SAS.

Practice Proofs!

More Proofs!