Question

A right angled triangle whose sides are $3cm,4cm$ and $5cm$ is revolved about the sides containing the right angle in two ways. 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 4 cm.

Hence their respective volumes are : $\frac{1}{3}\pi 3^2\left(4\right)and\frac{1}{3}\pi 4^2\left(3\right)$

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

C.S.A = $\pi \left(3\right)\left(5\right)and\pi \left(4\right)\left(5\right)=15\pi c{m}^{2}and20\pi c{m}^2$