Question

The volume of a circular iron rod of length $1m$ is $3850c{m}^3$. Find its diameter.

Answer 1

Given: Volume of cylindrical rod $=3850c{m}^3$

Length of rod $\left(h\right)=1m=100cm$

Let radius of the base of the rod be ${}^{\prime }{r}^{\prime }$.

Volume of cylindrical rod $=\pi r^{2}h$

$\therefore \pi r^{2}h=3850$

$\Rightarrow \frac{22}{7}\times r^2\times 100=3850$

$\Rightarrow r^2=\frac{3850\times 7}{2200}$

$\Rightarrow r^2=\frac{1225}{100}$

$\Rightarrow r^2={\left(\frac{35}{10}\right)}^2$

$\Rightarrow r^2=(3.5{)}^2$

$\therefore r=3.5cm.$

Hence, Diameter of the rod $=2r=2\times 3.5=7cm$