[Pramāṇa](https://indike.org/pramana/) › [Studies](https://indike.org/pramana/ins) › [Science, technology and education](https://indike.org/pramana/ins.science) › [Indian Mathematics](https://indike.org/pramana/ins.science.kaye-1915) › c7.39 # Indian Mathematics c7.39 Indian Mathematics c7.39 - **Language:** English ### [c7.39](https://indike.org/pramana/ins.science.kaye-1915.c7.39) where x and y are the diagonals of the cyclic quadrilateral (a, b, c, d). This (\*ii\*) is sometimes designated as ‘Brahmagupta's theorem’. - [Previous: c7.38](https://indike.org/pramana/ins.science.kaye-1915.c7.38) - [Next: c7.40](https://indike.org/pramana/ins.science.kaye-1915.c7.40) - [Up: c7](https://indike.org/pramana/ins.science.kaye-1915.c7) ## Cites (1) - [Brāhmasphuṭasiddhānta](https://indike.org/pramana/in.astro.siddhanta.early.brahmasphutasiddhanta) — Brahmagupta, Sanskrit --- Source: [https://indike.org/pramana/ins.science.kaye-1915.c7.39](https://indike.org/pramana/ins.science.kaye-1915.c7.39) · Pramāṇa