Question

If the radius and slant height of a cone are $20cm$ and $29cm$ respectively. Find its volume.

• A. $8800{cm}^3$
• B. $800{cm}^3$
• C. $880{cm}^3$
• D. None of these

Answer 1

The correct option is A $8800{cm}^3$

We have,

$r=20cm,l=29cm$.

We know, slant height

$l^2=r^2+h^2$.

So,

$h^2=(29{)}^2-(20{)}^2$

$h^2=841-400=441$

$h=21cm$.

We know that the volume of the cone

$=\frac{1}{3}\pi r^{2}h$

$=\frac{1}{3}\times \frac{22}{7}\times {20}^2\times 21$

$=8800c{m}^3$.

Hence, option $A$ is correct.