2005 AMC 10A Problems/Problem 23
BCDE is a square. Point A is chosen outside of BCDE such that angle BAC= 120 and AB=AC. Point F is chosen inside BCDE such that the triangles ABC and FCD are congruent. If AF=20, compute the area of BCDE.
(A)1/6 (B) 1/4 (C) 1/3 (D) 1/2 (E)2/3