To determine which theorem proves that two right triangles are congruent, we need to consider the characteristics of the given triangles.
The HL (Hypotenuse-Leg) Theorem specifically applies to right triangles. It states that if the hypotenuse and one leg of one right triangle are equal to the hypotenuse and one leg of another right triangle, then the two triangles are congruent.
Therefore, if your triangles are right triangles and you know the lengths of the hypotenuse and one leg of each triangle are equal, the answer would be:
HL Theorem