Question

A right triangle with sides 3 cm, 4 cm and 5 cm is rotated by the side of 3 cm to form a cone. the volume of the cone so formed is

Answer 1

When rotated with the side 3cm,
h=3cm
r=4cm
l=5cm
Volume of cone=(1/3)πr^2h
                          =(1/3)·(22/7)·4·4·3
On dividing and multiplying,                          
                          =(22/7)·4·4
                          =(352/7)
                          =50.28
                          =51 cm^3 [approximately]