The heights of two right circular cones are in the ratio 1 : 5 and the perimeter of their bases are in the ratio 5 : 3. Find the ratio of their volumes.
Answer & explanation
Correct answer: option 3
The heights of two right circular cones = 1 : 5
Perimeter of their bases = 5 : 3
We know that the ratio of the perimeter of base is equal to the ratio of the radius of the base of two cones.
So the ratio of the radius = 5 : 3
Now the ratio of their volumes = 52 × 1 : 32 × 5
= 25 : 45 = 5 : 9