Question

If the height and the radius of a cone are doubled, then its volume becomes _______________.

• A. Two times
• B. Four times
• C. Six times
• D. Eight times

Answer 1

Answer: (D)

Eight times

Volume of the cone in 1st case = $\frac{1}{3}\pi r^{2}h$

and volume of the cone in 2nd case $=\frac{1}{3}\pi (2r{)}^2\times (2h)=\frac{8\pi r^{2}h}{3}$.

$\therefore$ Its volume becomes $8$ times in second case.

Hence, option $D$ is correct.