Which of the following can be used to prove that triangle EFG is also a right triangle?
D. Prove that KL is equal to c by the Pythagorean Theorem
Since we know that both triangles have a and b in common, the same side lengths, then KL must be equal to c as well. Using the Pythagorean Theorem, this can be proved. And because the Pythagorean Theorem can only be used on a right triangle, then triangle EFG must also be a right triangle if KL if also equal to c.
