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

BD ≅ BD Reflexive Property

SSS Postulate

Given

Ex 1B:Try Another Proof!

Included �  What 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 3: Are the Triangles Congruent?

Ex 3B: Are the Triangles Congruent?

Ex 3C: Are the Triangles Congruent?

ΔACB ≅ ΔDBCby SSS

Practice Proofs!

More Proofs!