Question

Two right circular solid cylinders have radii in the ratio 3 : 5 and heights in the ratio 2 : 3. Find the ratio between their curved surface areas. 

Answer 1

Let the radii and height of two right circular cylinders be r₁, r₂ and h₁, h₂ respectively.

It is given that,

`r_1/r_2 = 3/5` and `h_1/h_2 = 2/3`

`"Curved surface area of cylinder 1"/"Curved surface area of cylinder 2" = (2pir_1h_1)/(2pir_2h_2)`

= `(r_1/r_2) xx (h_1/h_2)`

= `3/5 xx 2/3`

= `2/5`

∴ Ratio between their curved surface areas is 2 : 5.