Question 23Vertex $E$ 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 $\sqrt{1+\sqrt3},$ then the area of $\triangle ABF$ is $1$$\frac{\sqrt2}{2}$$\frac{\sqrt3}{2}$$4-2\sqrt3$$\frac12+\frac{\sqrt3}{4}$
