The area of a solid is equal to the sum of the areas of all surfaces of the solid. Often the surfaces are simple plane figures for which it is easy to compute the area.
The area of a cylinder with radius and height is: . (This formula is valid only for a straight cylinder: perpendicular to the base and top circles.)
The area of a sphere with radius is: .
The area of a cone with radius and height is: . (This formula is valid only for an upright cone with perpendciular to the base circle.)