So far we have calculated the circumference and the area of a circle, but at the ship yard we deal a lot with cylindrical objects, such as pipes. Let’s see how we can expand our knowledge to calculate the outer area of a pipe or a hollow cylinder. As the figure here illustrates, Calculating the outer area would be equivalent to cutting a hollow pipe along it’s length, perpendicular from it’s base, and unfolding it, until we flattened it as a piece of paper.
