22. The mean radius of the Earth is 6.37 x10^6 m and that of the Moon is 1.74 x10^8 cm . From these data calculate
(a) the ratio of the Earth's surface area to that of the Moon and (b) the ratio of the Earth's volume to that of the Moon. Recall that the surface area of a sphere is $4 \pi r^{2}$ and the volume of a sphere is $\frac{4}{3} \pi r^{3}$.
