Answer: The triangles are congruent by HL (hypotenuse leg)
We have two right triangles. The tickmarks show the legs are congruent. The hypotenuses are congruent because they overlap perfectly. The hypotenuses are a shared common side. Using HL, we can prove the triangles to be congruent.
Side note: You could use the pythagorean theorem to find the measure of the third pair of sides, and that would lead to using SSS.
