# A hemispherical tank is made up of an iron sheet 1 cm thick.

Question:

A hemispherical tank is made up of an iron sheet 1 cm thick. If the inner radius is 1 m, then find the volume of the iron used to make the tank.

Solution:

Given that,

Inner radius of the hemispherical tank = 1 m = r1

Thickness of the hemispherical tank = 1 cm = 0.01 m

Outer radius of hemispherical tank = (1 + 0.01) = 1.01 m = r2

Volume of iron used to make the tank

$=\frac{2}{3} \pi\left(r_{2}^{3}-r_{1}^{3}\right)$

$=\frac{2}{3} \times \frac{22}{7}\left[(1.01)^{3}-1^{3}\right]$

$=\frac{44}{21}[(1.0303)-1] \mathrm{m}^{3}$

$=0.06348 \mathrm{~m}^{3}$