The diameter of the moon is approximately one-fourth of the diameter of the earth.

Diameter of moon = 1/4th diameter of earth

Let the diameter of earth be d, so radius = d/2

Then diameter of moon = d/4

Radius $=\frac{\frac{\mathrm{d}}{2}}{4}=\frac{\mathrm{d}}{8}$

Volume of moon $=\frac{4}{3} \pi r^{3}=\frac{4}{3} \pi\left(\frac{d}{8}\right)^{3}=\frac{4}{3} \times \frac{1}{512} \pi d^{3}$

Volume of earth $=\frac{4}{3} \pi r^{3}=\frac{4}{3} \pi\left(\frac{d}{2}\right)^{3}=\frac{4}{3} \times \frac{1}{8} \pi d^{3}$

$\frac{\text { Volume of moon }}{\text { Volume of earth }}=\frac{\frac{4}{3} \times \frac{1}{512} \pi \mathrm{d}^{3}}{\frac{4}{3} \times \frac{1}{8} \pi \mathrm{d}^{3}}$

= 1/64

Thus the volume of the moon is 1/64 of volume of earth