Method:

Congruent triangles's first judgment method: SSS (edge to edge), that is, two triangles with three equal sides are congruent. (Basic facts, no need to prove)

Congruent triangles judgment method 2: SAS (Angle Edge), that is, two sides of a triangle are equal, and the included angle between the two sides also corresponds to the congruence of two equal triangles. (Basic facts, no need to prove)

Congruent triangles Judgment Method 3: ASA (Angle and Angle), that is, the two angles of a triangle are equal, and the sides of two corner clips are equal to two triangles. (Basic facts, no need to prove)

Congruent triangles Judgment Method 4: AAS (Angle Edge), that is, two angles of a triangle are equal, and the corresponding edges of two angles are equal to two triangles. (Method 3 can be proved by adding the triangle internal angle and 180 degrees)

Congruent triangles's judgment method 5: HL (hypotenuse and right-angled side), that is, two right-angled triangles with equal hypotenuse and right-angled side are the same. (It can be proved by method 2 plus Pythagorean theorem. )

Congruent triangles Judgment Method 6: SSA (Edge and Angle), that is, two sides of a triangle are equal, and the angles corresponding to the equal sides are also equal to two equal triangles. (Only obtuse triangles and right triangles can be used, not all acute triangles. )

Congruent triangles Judgment 7: The two triangles are the same before and after the plane motion (translation, rotation and folding) of the three major figures (not only triangles, but also this method is applicable to any plane figure, which is obtained after a lot of operations without proof).

Note: When writing, the letters must be written in the corresponding alphabetical order. Method 6 cannot be directly used for routine inspection.