Question

The radius of two cylinder are in the ratio 2:3 and their height are in the ratio 5:3 calculate the ratio of their curved surface areas

Answer 1

Ratio of radii r1:r2 = 2:3
ratio of heights h1:h2 = 5:3
Ratio of volume v1:v2=pi *r1^2*h1 : pi*r2^2*h2

v1/v2 = (pi*r1^2*h1 )/ (pi*r2^2*h2)
v1/v2 = (r1/r2)^2 *(h1/h2)
= (2/3)^2 * (5/3)
= 20/27

Ratio of curved surface=2*pi*r1*h1 : 2*pi*r2*h2
=(r1*h1)/(r2*h2)
=( r1/r2)* (h1/h2)
=(2/3)*(5/3)
= 10/9