A small cone of height 8 cm is cut off from a bigger cone to leave a frustum of height 16 cm. If the volume of the smaller cone is 160 cm'. find the volume of the frustum.

Answer 1

volume of smaller cone:
(1/3)π r^2 (8) = 160
r^2 = 60/π
r = √(60/π) = 4.3702 , (stored in my calculator's memory)

Make a cross-section view of the cone, which would have a height of 24 cm
if the radius of the large cone is x
then x/24 = r/8
x = 24(√(60/π)) / 8 = appr 13.1106 , also stored in memory

volume of large cone
= (1/3) π x^2 (24) = 4320

volume of frustum = 4320 - 160 cm^3

(my calculator gave me an exact value of 4320 which I can prove if needed)

Answer 2

no

Answer 3

not write

Answer 4

Good