Question

The volume of a cylindrical rod is 628 cm³. If its height is 20 cm, find the radius if its cross section.

Answer 1

$$\begin{gathered} \mathrm{Volume}\mathrm{of}\mathrm{culinder}={\mathrm{\pi r}}^2\mathrm{h} \\ \mathrm{Here}\mathrm{V}=628{\mathrm{cm}}^3\mathrm{and}\mathrm{h}=20\mathrm{cm} \\ \mathrm{So}\mathrm{r}=\sqrt{\frac{\mathrm{V}}{\mathrm{\pi h}}}=\sqrt{\frac{628}{3.14\times 20}}=1\mathrm{cm} \end{gathered}$$