Question

Find the curved surface area and total surface area of a cylinder, the diameter of whose base is 7 cm and height is 60 cm.

Answer 1

$$\begin{gathered} \mathrm{Let}r\mathit{}\mathrm{and}h\mathit{}\mathrm{be}\mathrm{the}\mathrm{radius}\mathrm{and}\mathrm{the}\mathrm{height}\mathrm{of}\mathrm{the}\mathrm{cylinder}. \\ \mathrm{Given}: \\ \mathrm{r}=\frac{7}{2}\mathrm{cm} \\ \mathrm{h}=60\mathrm{cm} \\ \mathrm{Curved}\mathrm{surface}\mathrm{area}\mathrm{of}\mathrm{the}\mathrm{cylinder}=2\mathrm{\pi }\times \mathrm{r}\times \mathrm{h} \\ =2\times \frac{22}{7}\times \frac{7}{2}\times 60 \\ =22\times 60=1320{\mathrm{cm}}^2 \\ \mathrm{Total}\mathrm{surface}\mathrm{area}\mathrm{of}\mathrm{the}\mathrm{cylinder}=2\mathrm{\pi }\times \mathrm{r}\times (\mathrm{r}+\mathrm{h}) \\ =2\times \frac{22}{7}\times \frac{7}{2}\times (\frac{7}{2}+60)=22\times \frac{127}{2}=11\times 127=1397{\mathrm{cm}}^2 \end{gathered}$$