Question

A hemispherical bowl is made of steel 0.5 cm thick. The inside radius of the bowl is 4 cm. Find the volume of steel used in making the bowl.

Answer 1

Internal radius of the hemispherical bowl = 4 cm
Thickness of a the bowl = 0.5 cm
Now, external radius of the bowl = (4 + 0.5 ) cm = 4.5 cm

Now, volume of steel used in making the bowl = volume of the shell
$$\begin{gathered} =\frac{2}{3}\mathrm{\pi }\left(4.5^3-4^3\right) \\ =\frac{2}{3}\times \frac{22}{7}\times \left(91.125-64\right) \\ =\frac{2}{3}\times \frac{22}{7}\times 27.125 \\ =56.83{\mathrm{cm}}^3 \end{gathered}$$

∴ 56.83 cm^₃ of steel is used in making the bowl .