Question

If the volume of a right circular cylinder with its height equal to the radius is $25\frac{1}{7}$, then the radius of the cylinder of is equal to

• A. $\pi$
• B. $2cm$
• C. $3cm$
• D. $4cm$

Answer 1

The correct option is B $2cm$

Given:

$h=4$

Volume of a cylinder $=\left(\pi r^2\right)h$

$=\pi r^2\times r$

$=\pi r^3$

Given $\pi r^3=25\times \frac{1}{7}$

$=\frac{176}{7}$

$\Rightarrow \frac{22}{7}{r}^3=\frac{176}{7}$

$\Rightarrow r^3=8\Rightarrow r=2cm$