Application of Power Theorem

Geometry

$AB$ and $CD$ are diameters of circle $O$ and they intersect at right angles. Point $M$ lies on circle $O$ and the secant connecting $M$ and $C$ intersect $AB$ at $G$ such that $CG = 4$ and $MG = 3.$

Assuming that $\pi = \frac{22}7,$ what is the area of circle $O?$