Triangle JKL and triangle PQR are shown above. If ∠J is congruent to ∠P, which of the following must be true in order to prove that triangles JKL and PQR are congruent?

If two angles and the included side of one triangle are congruent to corresponding parts of another triangle, the triangles are congruent. Since angles J and L are congruent to angles P and R, respectively, and the side lengths between each pair of angles, JL and PR, are also equal, then it can be proven that triangles JKL and PQR are congruent.