Question

When a triangle is said to be congruent?

Answer 1

Find when the triangles are congruent.

1. A triangle is said to be congruent when all the three sides of that triangle are equal in length and the angles of the corresponding sides are also identical.
2. Meaning of congruence: Triangles are said to be congruent if it is possible to superpose one of them on the other so that they coincide throughout.
3. The sign of congruence is $\cong$
4. There are four congruency principles that are used to determine if two triangles are congruent. i.e. SAS, ASA, AAS, SSS, RHS

If two angles and the included side of a triangle are congruent to two angles and the included side of another triangle, then the two triangles are congruent.

Hence this is the way to check the congruency of triangles.