Question

how to prove two triangles are congruent

Answer 1

we can prove two triangles as congruent using congruence rules
they are :
SAS
ASA
SSS
RHS

Answer 2

Congruent Figures :

Those figures which covers each other/one another exactly then they are congruent Figures.

There are 4 ways by which we can prove any 2 triangles as congruent :

If they are having -

★ SSS : Side Side Side

Three pairs of side are equal then the triangles are congruent.

★ ASA : Angle Side Angle / AAS : Angle Angle Side

If any 2 pairs of angles and 1 side are equal then the triangles are congruent.

★ SAS : Side Angle Side

If any two pairs of sides and the included angle are equal then the triangles are congruent.

★ RHS : Right Hypotenuse Side

If any right angle triangles are having their hypotenuse and a pair of sides equal then they are congruent.