A water tower is a right circular cylinder 21 m high with a radius of 7 m. Determine the area that needs to be covered if its exterior is painted.

Answer 1

There are 2 sections that would need to be painted.

Around the sides - If you were to unroll this piece, it would actually be a rectangle. One side would be the height and one side would be the Circumference. C = πd

SA = height x circumference

SA = 21 x π(14) = 294π

For the top the area would be area of the circle = πr²

SA = π7² = 49π

Total = 294π+49π = 343π m²