# Proving Triangles are Congruent by SSS, SAS, and ASA

Students learn the following postulates related to congruent triangles. If the three sides of one triangle are congruent to the three sides of another triangle, then the triangles are congruent (Side-Side-Side or SSS). If two sides and the included angle of one triangle are congruent to two sides and the included angle of another triangle, then the triangles are congruent (Side-Angle-Side or SAS). If two angles and the included side of one triangle are congruent to two angles and the included side of another triangle, then the triangles are congruent (Angle-Side-Angle or ASA). Students are then asked to determine whether given triangles are congruent, and name the postulate that is used.