Key Concepts: Congruent Triangles

Congruent Triangles

Two triangles are congruent if all their corresponding sides and corresponding angles are congruent. When listing congruent triangles, the order of vertices matters — it shows which parts correspond.

CPCTC

Corresponding Parts of Congruent Triangles are Congruent (CPCTC). Once two triangles are proven congruent, ALL corresponding parts are congruent.

Third Angles Theorem

If two angles of one Triangle are congruent to two angles of another Triangle, then the third angles are also congruent.