Question

Find the total surface area of a hemisphere of radius $10\mathrm{cm}$. [Use $\mathrm{\pi }=3.14$]

Answer 1

Surface area of given hemisphere

Given, radius of hemisphere, $r=10\mathrm{cm}$

Assuming that the hemisphere is closed,

Total surface area of closed hemisphere $=3{\mathrm{\pi r}}^2$

$$\begin{gathered} =3\times 3.14\times {10}^2 \\ =942{\mathrm{cm}}^2 \end{gathered}$$

Therefore, the total surface area of given hemisphere is $942{\mathrm{cm}}^2$

Note:

A closed hemisphere is also called a solid hemisphere

An open hemisphere is is a hemisphere that is hollow, like a bowl. It is also called a hollow hemisphere

The total surface area of an open hemisphere $=2{\mathrm{\pi r}}^2$