Question

The curved surface area of a cylinder is reduced by ______ per cent if the height is half of the original height.

Answer 1

The curved surface area of a cylinder is reduced by 50 per cent if the height is half of the original height.

Explanation:

The curved surface area of a cylinder with radius r and height h = 2πrh

If the height is halved, then new curved surface area of cylinder = `2pir h/2 = pirh`

∴ Percentage reduction in curved surface area = `(2pirh - pirh)/(2pirh) xx 100`

= `(pirh)/(2pirh) xx 100`

= 50%