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1989 AJHSME Problems/Problem 15

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Problem

The area of the shaded region \text{BEDC} in parallelogram \text{ABCD} is

unitsize(10);pair A,B,C,D,E;A=origin; B=(4,8); C=(14,8); D=(10,0); E=(4,0);draw(A--B--C--D--cycle);fill(B--E--D--C--cycle,gra...

\text{(A)}\ 24 \qquad \text{(B)}\ 48 \qquad \text{(C)}\ 60 \qquad \text{(D)}\ 64 \qquad \text{(E)}\ 80

Solution

Let !ABC! denote the area of figure ABC.

Clearly, !BEDC!=!ABCD!-!ABE!. Using basic area formulas, !ABCD!=(BC)(BE)=80 !ABE!=(BE)(AE)/2 = 4(AE)

Since AE+EC=BC=10 and EC=6, AE=4 and the area of \triangle ABE is 4(4)=16.

Finally, we have !BEDC!=80-16=64\rightarrow \boxed{\text{D}}

See Also

1989 AJHSME (ProblemsResources)
Preceded by
Problem 14
Followed by
Problem 16
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