Question

12. A cylinder has radius r and heighth. If the radius and height of a cylinder are doubled, then a new cylinder
is obtained. Find the ratio of curved surface area of the original cylinder to that of the new cylinder​

Answer 1

Answer : 1:4

explaination:

curved surface area of a cylinder =

$2\pi \: rh$

In the original cylinder radius = r and height = h

In the new cylinder radius = 2r and height = 2h

so CSA of first cylinder = 2πrh

and CSA of second cylinder = 2π x 2r x 2h = 8πrh

Ratio = 2πrh:8πrh = 1 : 4