Question

A right angled triangle of sides $3cm$, $4cm$ and $5cm$ is rotated about the side $3cm$ then, the volume of the cone formed is .

• A. $8\pi c{m}^3$
• B. $9\pi c{m}^3$
• C. $12\pi c{m}^3$
• D. $16\pi c{m}^3$

Answer 1

The correct option is D $16\pi c{m}^3$

We know that,
Volume of the cone is $\frac{1}{3}\pi r^{2}h$.

Now,
When triangle is rotated,
height of cone formed is $3cm$.
radius of cone formed is $4cm$.

Thus, volume of the cone
$=\frac{1}{3}\pi \left(4^2\right)\left(3\right)$
$=16\pi c{m}^3$