Section 4.2 – Triangle Congruence

There are a few ways to prove triangles congruent. You can prove that all 3 pairs of corresponding sides are congruent and all 3 pairs of corresponding angles are congruent. Or, you can use the following “shortcuts.”

Side-Side-Side (SSS) Congruence Postulate

If the three sides of one triangle are congruent to the corresponding three sides of another triangle, then the two triangles are congruent.

Side-Angle-Side (SAS) Congruent Theorem

If two sides and the included angle of one triangle are congruent to the corresponding two sides and included angle of another triangle, then the two triangles are congruent.

Angle-Side-Angle (ASA) Congruence Theorem

If two angles and the included side of one triangle are congruent to the corresponding two angles and included side of another triangle, then the two triangles are congruent.