13. $A B C D$ and $D E F G$ are two rectangles, and $A B=D E$ $=15, B C=E F=9 . E$ is on $A B$, and $E F$ intersects $B C$ at $H$. Then the area of $D E H C$ is ( ).
(A) 60
(B) 65
(C) 70
(D) 75
(E) None of the above answers is correct
13. (D) By symmetry, $C$ should be on $F G$, and the area of $D E H C$ is twice the area of $\triangle D E H$. By the Pythagorean theorem, $E A=$ 12, so, $B E=3$. Then, by the similarity of $\triangle A D E$ and $\triangle B E H$, we get $H E=5$. Therefore, the area of $\triangle D E H$ is $\frac{75}{2}$.