cone and frustrum question?

Question

there is a cone of height 6cm and base radius of 8cm.

It is then cut in half to form a smaller cone and frustrum.

The height of the smaller cone is then 3cm, and the height of the frustrum is 3cm. The base radius of the frustrum is still 8cm

Show that the volume of the frustrum is 112*pi*cm^3.

PLEASE DON'T USE A CALCUALOR AS THIS IS A NON CALCULATOR QUESTION... JUST LEAVE ANSWER AS A MULTIPLE OF PIE.
thanks

Answer 1

Vol of whole cone = 1/3 (base x ht) = 1/3 (pi x 8^2 x 6)

Vol of reduced cone = 1/3 (base x ht) = 1/3 (pi x 4^2 x 3)

Vol of frustrum = difference = 1/3 x pi x (64x6 - 16x3) =
pi x (128-16)= pi x 112