Liu Hui

Liu Hui was a Chinese mathematician active in the 3rd century AD during the Three Kingdoms period, best known for his 263 AD commentary on The Nine Chapters on the Mathematical Art, the most influential Chinese mathematical text of antiquity. His contributions include a proof of the Pythagorean theorem, results in solid geometry, and a substantially improved approximation of pi using a method of inscribed polygons. He also developed systematic methods for solving systems of linear equations with multiple unknowns and, in his separate Sea Island Mathematical Manual, described surveying techniques for measuring distances and heights using right triangles.