Question

The diameter of a cylinder is 28 cm and its height is 40 cm. Find the curved surface area, total surface area and the volume of the cylinder.

Answer 1

Here, r = 28/2 = 14 cm; h = 40 cm

$$\begin{gathered} \mathrm{Curved}\mathrm{surface}\mathrm{area}\mathrm{of}\mathrm{the}\mathrm{cylinder}=2\mathrm{\pi }rh \\ =2\times \frac{22}{7}\times 14\times 40{\mathrm{cm}}^2 \\ =2\times 22\times 2\times 40{\mathrm{cm}}^2 \\ =3520{\mathrm{cm}}^2 \end{gathered}$$


$$\begin{gathered} \mathrm{Total}\mathrm{surface}\mathrm{area}\mathrm{of}\mathrm{the}\mathrm{cylinder}=2\mathrm{\pi }rh+2\mathrm{\pi }{r}^2 \\ =\left(3520+2\times \frac{22}{7}\times {14}^2\right){\mathrm{cm}}^2 \\ =(3520+1232)=4752{\mathrm{cm}}^2 \end{gathered}$$

$$\begin{gathered} \therefore \mathrm{Volume}\mathrm{of}\mathrm{the}\mathrm{cylinder}=\mathrm{\pi }{r}^{\mathit{2}}h \\ =\frac{22}{7}\times {14}^2\times 40{\mathrm{cm}}^3 \\ =22\times 14\times 2\times 40{\mathrm{cm}}^3 \\ =24640{\mathrm{cm}}^3 \end{gathered}$$