The base radii of two right circular cones of the same height are in the ratio 3:5. Find the ratio of their volumes.

Explanation

let radius of 1st cone`r=3x`

radius of 2nd cone `R=5x`

both equal height `=h`

so ratio of their volume`=[(1/3)pi(r^2)h]/[(1/3)pi(R^2)h]`

`=[(1/3)pi((3x)^2)h]/[(1/3)pi((5x)^2)h]`

`=9/25`