The volume of a solid with known cross sections can be calculated by taking the definite integral of all the cross sections, with being equal to a single section. For example, suppose we want to find the volume of the solid with each cross section being a circle, with the diameter of each cross section being the distance between and the x-axis from 0 to 2. Since one cross section will be equal to and , a single cross section will have an area of or . The volume will therefore be equal to