Question

A cylinder’s radius is reduced to 2004-06-01-04-00_files/i0480001.jpg its original size and the height is quadrupled. How has the volume of the cylinder changed?

Answer 1

I can't answer this question if we don't know by what scale the cylinder's radius was reduced. Luckily, I found the same problem that says the radius was reduced to 2/5. So, we find the ratio of both volumes.

V₁ = πr₁²h₁
V₂ = πr₂²h₂

where r₂ = 2/5*r₁ and h₂ = 4h₁

V₂/V₁ = π(2/5*r₁ )²(4h₁)/πr₁²h₁= 8/5 or 1.6

Thus, the volume has increased more by 60%.