Suppose a water tank in the shape of a right circular cylinder is thiry feet long and eight feet in diameter. How much sheet metal was used in its construction? This is an exampleo f a real life application for finding the surface are of a cylinder. Anyone from a lumber to a painter would need ot know the formula. A painter would need the formula so that they can decide how much paint they need to get if they are painting an object in the shape of a cylinder.

Also, someone who makes toys would need to know how much material is needed if they were making an object in the shape of a cylinder. Surface area can also be used if you are trying to find out how much wrapping paper to wrap a gift. Surface area is used for many things rom gifts to plumbing.