Question

A right angled triangle whose sides are $3cm,4cm$ and $5cm$ is revolved about the sides containing the right angle in two days. Find the difference in volumes of the two cones so formed. Also,find their curved surfaces.

Answer 1

The sides containing the right angle are $3cm$ and $4cm$.

Since, volumn of cone given as $=\frac{1}{3}\pi r^{2}h$

Hence their respective volumes are :

$\frac{1}{3}\pi \left(3{)}^2\right(4)$ and $\frac{1}{3}\pi \left(4{)}^2\right(3)$

Difference :

$=\frac{1}{3}\pi (48-36)=4\pi c{m}^3$

Curved surface are of cone given as$=\pi rh$

Hence,

C.S.A $=\pi \left(3\right)\left(5\right)$ and $\pi \left(4\right)\left(5\right)$

C.S.A = $15\pi c{m}^2$and $20\pi c{m}^2$