CAYLEY 2007 Problem 19

Past Contests CAYLEY CAYLEY - 2007
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In the diagram, the four points have coordinates A(0,1),B(1,3),C(5,2), and D(4,0). What is the area of quadrilateral ABCD?

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Answer Choices
A. 9
B. 3
C. 6
D. \sqrt{85}
E. 2\sqrt5+2\sqrt{17}