Definition of congruent triangles (CPCTC) - two triangles are congruent if and only if their corresponding parts are congruent

Properties: congruence of triangles is reflexive, symmetric, and transitive

SSS Congruency - If the sides of one triangle are congruent to the sides of a second triangle, then the triangles are congruent

SAS Congruency - If two sides and the included angle of one triangle are congruent to two sides and the included angle of annother triangle, then the triangles arre congruent

ASA Congruency - if two angle sand the included side of one triangle are congruent to two angles and the included side of another triangle, then the triangles are congruent

AAS Congruency - If two angles and a non-included side of one triangle are congruent to the corresponding two angles and side of a second triangle, then the triangles are congruent

Isosceles Triangle Theorem - If two sides of a triangle are congruent, then the angles opposite those sides are congruent. If two angles of a triangle are congruent, then the sides opposite those angles are congruent.

*Explorations with GSP