if the altitude of right cylinder is doubled, what happens to its surface area?

Answer 1

If it is a hollow cylihder, the surface area is doubled also.

Answer 2

The surface area of the 'cylinderical' part doubles. But the areas of the ends stay constant. The total area is the sum of those.

For a cylinder of radius r and length l, the area of each end is simply Ae = πr²

The area lf the cylindrical side is
As = 2πrl

So the total surface area is
A = Ae + Ae + As = πr² + πr² + 2πrl = 2πr² + 2πrl
which is frequently factored and written as
A = 2πr(r+l)

Hope that helps.


Doug