Question

The volume of a cone is $18480c{m}^3$. If the height of the cone is $40cm$, find the radius of its base.

• A. $31cm$
• B. $21cm$
• C. $22cm$
• D. $20cm$

Answer 1

Answer: (B)

$21cm$

Volume of cone $=18480$${cm}^3$

$\Rightarrow \frac{1}{3}\pi r^{2}h=18480\Rightarrow r^2=\frac{18486\times 3\times 7}{22\times 40}=21\times 21$

$\Rightarrow r=\sqrt{21\times 21}=21cm$