Problem:
In rectangle ABCD,AB=6,AD=30, and G is the midpoint of AD. Segment AB is extended 2 units beyond B to point E, and F is the intersection of ED and BC. What is the area of BFDG?
Answer Choices:
A. 2133β
B. 67
C. 2135β
D. 68
E. 2137β
Solution:
Because β³EBF is similar to β³EAD, it follows that ADBFβ=AEBEβ, or 30BFβ=82β, giving BF=215β. The area of trapezoid BFDG is
21βh(b1β+b2β)=21ββ
ABβ
(BF+GD)=21ββ
6β
(215β+15)=(C)2135ββ.
The problems on this page are the property of the MAA's American Mathematics Competitions