In the figure above, the triangle \(ABC\) is inscribed in a semicircle, with center \(O.\) If \(CÔA = 120^{\circ}\) and

[Gmat_mission]

In the figure above, the triangle \(ABC\) is inscribed in a semicircle, with center \(O.\) If \(CÔA = 120^{\circ}\) and \(AC = 3\sqrt3,\) what is the radius of the circle?

(a) \(\dfrac{4\sqrt3}5\)
(b) \(3\)
(c) \(2\sqrt3\)
(d) \(4\)
(e) \(9\)

Answer: B

Source: Official Guide