Theory:

Sphere:
A sphere is a three-dimensional figure obtained by the revolution of a semicircle about its diameter as an axis.
Volume of a sphere:
Let $$r$$ be the radius of a sphere.

Volume of a sphere $$=$$ $\frac{4}{3}\mathrm{\pi }{r}^{3}$ cu. units

Example:
Find the mass of $$5$$ spherical balls, each of diameter $$8.4$$ $$cm$$.

Solution:

Diameter of the spherical ball $$(d)$$ $$=$$ $$8.4 \ cm$$

Radius of the spherical ball $$(r)$$ $$=$$ $\frac{d}{2}=\frac{8.4}{2}=4.2$ $$cm$$

Volume of the spherical ball $$=$$ $\frac{4}{3}\mathrm{\pi }{r}^{3}$ cu. units

$$=$$ $\frac{4}{3}×\frac{22}{7}×{\left(4.2\right)}^{3}$

$$=$$ $\frac{4}{3}×\frac{22}{7}×4.2×4.2×4.2$

$$=$$ $$310.464$$

Volume of the spherical ball is $$310.464 \ cm^3$$.

Volume of $$5$$ spherical balls:

$$=$$ $$310.464 \times 5$$

$$=$$ $$1552.32$$

Therefore, the volume of $$5$$ spherical balls is $$1552.32 \ cm^3$$.
Important!
The value of $$\pi$$ should be taken as $\frac{22}{7}$ unless its value shared in the problem.