Problem: Vertex E of equilateral triangle ABE is in the interior of square ABCD, and F is the point of intersection of diagonal BD and line segment AE. If length AB is 1+3 then the area of △ABF is
Answer Choices:
A. 1
B. 22
C. 23
D. 4−23
E. 21+43
Solution:
Let FG be an altitude of △AFB, and let x denote the length of AG. From the adjoining figure it may be seen that
