# Problem #2318

 2318 Convex quadrilateral $ABCD$ has $AB=3$, $BC=4$, $CD=13$, $AD=12$, and $\angle ABC=90^{\circ}$, as shown. What is the area of the quadrilateral? $[asy] pair A=(0,0), B=(-3,0), C=(-3,-4), D=(48/5,-36/5); draw(A--B--C--D--A); label("A",A,N); label("B",B,NW); label("C",C,SW); label("D",D,E); draw(rightanglemark(A,B,C,25)); [/asy]$ $\textbf{(A)}\ 30\qquad\textbf{(B)}\ 36\qquad\textbf{(C)}\ 40\qquad\textbf{(D)}\ 48\qquad\textbf{(E)}\ 58.5$ This problem is copyrighted by the American Mathematics Competitions.
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