Volume, in mathematics, the amount of space occupied by a three-dimensional solid body. Formulas exist for computing the volumes of familiar solids, including cones, cubes, cylinders, prisms, pyramids, and spheres. The volume of a cone, for instance, is equal to one-third the area of its (circular) base times its height, or €(pr²)h. Volume is measured in terms of cubic units, such as cubic centimeters and cubic meters in the metric system of weights and measures, or cubic inches and cubic feet in the English system. Volume may also be expressed in liters and gallons, units generally used in measuring amounts of liquid, and in bushels, a unit used in measuring amounts of solids that can be poured (such as grain). See also Density.