Question

The radii of two similar cones are 1 and 2.5. What is the ratio of their volumes?

Answer 1

Assuming the cones are the same height, then

V1 = pi * r^2 * h/3 = 3.14159*1^2*h/3

V2 = 3.14159*2.5^2*h/3 = 3.14159*6.25*h/3

V1/V2=(3.14159*h/3)/(3.14159*6.25)*h/3

V1/V2 = 1/6.25 = .16

V2/V1=(3.14159*6.25)*h/3/(3.14159*h/3)

V2/V1=6.25/1 = 6.25