Question:
A solid cylinder of radius r and height h is placed over other cylinder of same height and radius. The total surface area of the shape so formed is 4πrh +
4πr2.
Solution:
False
Since, the total surface area of cylinder of radius, rand height, h = 2πrh + 2πr2 When one cylinder is placed over the other cylinder of same height
and radius,
then height of the new cylinder = 2 h
and radius of the new cylinder = r
∴ Total surface area of the new cylinder = 2πr(2h) + 2πr2 = 4πrh + 2πr2