Brahmagupta Theorem

Brahmagupta's theorem is a result in geometry about cyclic quadrilaterals whose diagonals are perpendicular to each other. It states that if such a quadrilateral has its diagonals meeting at a point, then the line drawn perpendicular to one side from that intersection point will always pass through the midpoint of the opposite side. The theorem is named for the Indian mathematician Brahmagupta, who lived from 598 to 668. It is proved by dropping a perpendicular from the point where the diagonals intersect to one side of the quadrilateral and showing that the line through that new point and the original intersection point meets the opposite side exactly at its midpoint.