Congruent Triangles - Two sides and included angle (SAS) Definition: Triangles are congruent if any pair of corresponding sides and their included angles are equal in both triangles. There are five ways to test that two triangles are congruent. This is one of them (SAS).
If two triangles have two congruentsides and a congruent non included angle, then triangles are NOT NECESSARILLY congruent. This is why there is no Side Side Angle (SSA) and there is no Angle Side Side (ASS) postulate.