When proving triangles congruent, there are a few methods generally used.

SSS - If three sides of a triangle and congruent to three sides of a second triangle, the 2 triangles are congruent.

SAS - If 2 sides and the included angle of one triangle are congruent to 2 sides and the included angle of another triangle, then the triangles are congruent.

ASA - If 2 angles and the included side of one triangle are congruent to 2 angles and the included side of another triangle, then the triangles are congruent.

AAS - If 2 angles and the non included side of one triangle are congruent to 2 angles and the non included side of another triangle, then the triangles are congruent.

HL - In a right triangle, if the hypotenuse and a leg of one triangle are congruent to the hypotenuse and a leg of another triangle, then the triangles are congruent.