Generally speaking, the verification of two congruent triangles is judged by the hypotenuse and right-angled side (HL) of side (SSS), corner (SAS), corner (ASA), corner (AAS) and right-angled triangle. There should be six kinds of judgment methods, but congruent triangles can't use angle angle (AAA) and edge angle (SSA), so there are only four kinds of judgment methods.

Two triangles that can completely overlap are called congruent triangles, and the three sides and angles of the two triangles are equal. Congruent triangles refers to two congruent triangles whose three sides and three angles are equal. Congruent triangles is one of congruences in geometry. According to congruence transformation, two congruent triangles are still congruence after translation, rotation and folding.