History of Hindu Mathematics: A Source Book v2.c17.s19.t1.15

v2.c17.s19.t1.15

**Rational Inscribed Quadrilaterals.** Brahmagupta formulated a remarkable proposition: To find all quadrilaterals which will be inscribable within circles and whose sides, diagonals, perpendiculars, segments (of sides and diagonals by perpendiculars from vertices as also of diagonals by their intersection), areas, and also the diameters of the circumscribed circles will be expressible in integers. Such quadrilaterals are called Brahmagupta quadrilaterals.