For the Pair of Similar Triangles, Find the Length of the Indicated

Multiple Choice

For the pair of similar triangles, find the length of the indicated side.
-In the left triangle, the hypotenuse has length 39 , and the longer leg has length 36 . In the right triangle, the hypotenuse has length 13 , the longer leg has length 12 , and the shorter leg has length 5 . Find the length, $x$ , of the shorter leg of the left triangle.

A) $x = 5$
B) $x = 9$
C) $x = 15$
D) $x = 20$