2007 AMC 10B Problem 7

All sides of the convex pentagon ABCDE are of equal length, and \angle A= \angle B = 90^\circ. What is the degree measure of \angle E?

\textbf{(A) } 90 \qquad\textbf{(B) } 108 \qquad\textbf{(C) } 120 \qquad\textbf{(D) } 144 \qquad\textbf{(E) } 150

Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.