Question

Help!! so hard!!! Help me!!!

Answer 1

Triangle ADE is equilateral so each of its interior angles haves measure 60 degrees. AB is a diameter of the circle because it passes through C. Then AB is perpendicular to ED, which means triangle ABD is a 30-60-90 triangle.

In this triangle, the lengths of BD, AD, and AB occur in a ratio of 1 to 2 to $\sqrt3$, so that AB has length $(\sqrt3)^2=3$.

So the circle has diameter 3, or radius 3/2, and its area is $\left(\dfrac32\right)^2\pi=\boxed{\dfrac{9\pi}4}$ and the answer would be C.