On a flawed, 16th-century derivation of Brahmagupta's formula for the area of a cyclic quadrilateral

Forum Geometricorum

Eisso J. Atzema¹ 

DOI  :  

学科分类：数学（综合）

来源: Forum Geometricorum: a journal on classical euclidean geometry

【 摘 要 】

Around 1545, the Indian commentator Ganesa suggested an interesting, but ultimately flawed, derivation of Brahmagupta`s formula for the area of a cyclic quadrilateral in terms of its sides. In this paper we show that Ganesa`s approach is actually valid and that his proof is easily fixed. We will also investigate to what extent his idea can be generalized to arbitrary (convex) quadrilaterals.

【 授权许可】

Unknown