Question

119. The ratio between the curved surface area and the total surface area
of a right circular cylinder is 1:2. Find the ratio between the height
and radius of the cylinder.​

Answer 1

given, csa : tsa of cylinder = 1:2

2πrh / 2πr(r+h) = 1/2

h/(r+h) = 1/2

by cross multiplication, we get

2h = r+h

2h-h = r

therefore h=r

by calculating, we get height is equal to radius. then ratio of their height and radius is

height of cylinder : radius of cylinder = 1:1