Question

In the two triangles ABC and DEF, AB = DE and AC = EF. Name two angles from the two triangles that must be equal so that the two triangles are congruent. Give reason for your answer.

Answer 1

The required two angles are ∠A and ∠E. When ∠A = ∠E, ∆ ABC ≅ ∆ EDF by SAS criterion.