The volume of a pyramid (also any cone) is formula_1, where "b" is the area of the base and "h" the height from the base to the apex. This works for any polygon, regular or non-regular, and any location of the apex, provided that "h" is measured as the perpendicular distance from the plane containing the base. In 499 AD Aryabhata, a mathematician-astronomer from the classical age of Indian mathematics and Indian astronomy, used this method in the "Aryabhatiya" (section 2.6).