To use the hl theorem to prove two triangles are congruent, the triangles must be right triangles. which other conditions must also be met? . a. the triangles have congruent hypotenuses and two pairs of congruent legs. b. the triangles have congruent hypotenuses and one pair of congruent legs. c. the triangles have two pairs of congruent legs. d. the triangles have congruent hypotenuses .