Question

A right angled triangle with sides 3cm and 4cm is revolved around its hypotenuse .

Find the volume of double of double cone formed.

Answer 1

about the side through triangle is revolved is the height of the cone and rest one is the radius of the cone
here when the cone is revolved about 4cm,
then
here r=3cm
and h=4cm
so volume of cone =1/3*π(3)(3)(4)
now volume = 12πcm3
but when the is revolved about 3cm
then
height of the cone =3cm
and
the radius of the cone =4cm
now, volume of the cone =1/3*π(4)(4)(3)
volume= 16πcm3