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# 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.

Given :
Inner radius of hemispherical tank (r) = 1 m
Thickness of hemispherical tank 1 cm = 0.01 m
Outer radius of hemispherical tank (R) = (1 + 0.01) m = 1.01 m

We know that,

Volume of iron is used to make such a tank
= $$\frac{2}{3}{\pi}({R}^3 - {r}^3)$$
= $$\frac{2}{3} × \frac{22}{7} × ({1.01}^3 - {1}^3)$$ $${m}^3$$
= $$\frac{44}{21} × (1.030301 - 1)$$ $${m}^3$$
= 0.06348 $${m}^3$$ (approx.)

Therefore, the volume of the iron used to make the tank is 0.06348 $${m}^3$$.