Explanation: O is the center of the circle \(\frac{1}{2}\times6\times CD=\frac{\sqrt{3}}{4}\times6^{2}\) [both are formulae to determine area of the equilateral triangle] \(\therefore CD=3\sqrt{3}\) \(\therefore OD=\sqrt{3}\) Now, \(OD^{2}+AD^{2}=OA^{2}\) \((\sqrt{3})^{2}+(3)^{2}=OA^{2}\) \(\therefore OA=\sqrt{12}\) \(Area=12\pi\) (Ans. B)
