K. R. S. Sastry, Construction of Brahmagupta n-gons,
Forum Geometricorum, 5 (2005) 119--126.

Abstract: The Indian mathematician Brahmagupta's contributions to mathematics and astronomy are well known. His principle of adjoining Pythagorean triangles to construct general Heron triangles and cyclic quadrilaterals having integer sides, diagonals and area can be employed to appropriate Heron triangles themselves to construct any inscribable n-gon, n > or = 3, that has integer sides, diagonals and area. To do so we need a different description of Heron triangles by families that contain a common angle. In this paper we describe such a construction.

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