Statement (1) alone is tempting if you are familiar with the right triangles that tend to be
tested over and over on the GMAT; however, we don’t know from statement (1) that ABC is a right
triangle, so we should cross off A and D.
With only statement (2), we certainly don’t have enough information to answer the question, so B
can be eliminated. Together, though, we can complete the picture of a right triangle with two
known sides, which means we can figure out the third side using Pythagorean Theorem, and our
answer is C. (Since the squares of the two legs add up to 169, the hypotenuse is 13.)