# GRE problem

Geometry Level 3

If $$AB=BC$$, $$AB=a$$, $$DE=b$$, and $$\angle ABC =\angle EDC = 90^{\circ}$$ then which of the following is an expression for the area of quadrilateral $$ABDE?$$

A. $$\large\frac{a^2}{2}-\frac{b^2}{2}$$

B. $$\large\frac{a^2}{2}+\frac{b^2}{2}$$

C. $$\large\frac{a^2}{4}-\frac{ab}{2}$$

D. $$\large a^2-b^2$$

E. $$\large\frac{a^2}{4}+\frac{ab}{2}$$

×