970-1036

Arab mathematician and astronomer known for his commentary on the Spherics by Menelaus. Mansur came from the Banu Iraq family, who ruled Khwarazm near the Aral Sea, but in 995 lost power; thereafter, he served in the courts of other rulers. A student of Abul Wefa, Mansur was later teacher to al-Biruni and wrote as many as 25 works, of which seven were on mathematics. His work on the Spherics is particularly noteworthy because the original Greek manuscript has been lost. In addition, Mansur contributed to the development of trigonometry by discovering the sine law a/sin A = b/sin B = c/sin C.