Step 1: Remember the AAA congruent theorem

            DEFINITION: In two triangles, if the angles are equal, then the sides

            opposite to the equal angles are in the same ratio (or proportional) and

             hence the two triangles are similar.

Step 2: Find the two triangles with three pairs of congruent angles.

               EXAMPLE:  \angle P =   \angle L

                                   \angle Q = \angle M

                                   \angle R = \angle N

Step 3: Conclude that the given triangles are congruent if the two triangles with

             three pairs of congruent angles.

            EXAMPLE: three angles of △PQR are congruent to three angles

                             of △LMN, so these triangles are congruent by the AAA Theorem.