Question

The curved surface area of a cylindrical road is 132 cm². Find its length if the radius is 0.35 cm.

Answer 1

$$\begin{gathered} \mathrm{Consider}h\mathrm{to}\mathrm{be}\mathrm{the}\mathrm{height}\mathrm{of}\mathrm{the}\mathrm{cylindrical}\mathrm{rod}. \\ \mathrm{Given}: \\ \mathrm{Radius},r=0.35\mathrm{cm} \\ \mathrm{Curved}\mathrm{surface}\mathrm{area}=132{\mathrm{cm}}^2 \\ \mathrm{We}\mathrm{know}: \\ \mathrm{Curved}\mathrm{surface}\mathrm{area}=2\times \mathrm{\pi }\times \mathrm{r}\times \mathrm{h} \\ 132=2\times \frac{22}{7}\times 0.35\times \mathrm{h} \\ h=\frac{132\times 7}{2\times 22\times 0.35} \\ h=60 \\ \mathrm{Therefore},\mathrm{the}\mathrm{length}\mathrm{of}\mathrm{the}\mathrm{cylindrical}\mathrm{rod}\mathrm{is}60\mathrm{cm}. \end{gathered}$$