Question

The radius of two cylinders are in the ratio 2:3 and their heights are in the ratio 5:3 . Calculate the ratio of their c.s.a .

Answer 1

What is c.s.a. tell me

Answer 2

First cylinder
radius = 2x
height = 5x

Now,

Second cylinder
radius = 3x
height = 3x

so,

Formula of CSA of cylinder = 2πrh

Ratio of the first and second cylinders will be

$= \frac{2\pi \: rh}{2\pi \: rh} \\ \\ = \frac { \cancel 2 \times \cancel\pi \times \: 2x \times 5x}{\cancel2 \times \cancel\pi \times 3x \times 3x} \\ \\ = \frac{ 10 \: \cancel{x}^{2} }{ 9\cancel{x}^{2} } \\ \\ = 10 : 9$

Hence,
the ratio of the CSA of cylinders = 10:9