Abu Raihan Al-Biruni (أبو ريحان البيروني) (September 15, 973 - December 13, 1048) was a Muslim mathematician, astronomer, physicist, scholar, encyclopedist and teacher of Central Asian origin, who contributed greatly to the fields of mathematics and science. He was born in Khwarazm in what is now known to be as Uzbekistan but was then within the borders of Persian Empire. He studied mathematics and astronomy under Abu Nasr Mansur. He wrote his books in Persian and Arabic. Some of his notable achievements included:
At age 17, he calculated the latitude of Kath, Khwarazm, using the maximum altitude of the sun.
By age 22, he had written several short works, including a study of map projections, "Cartography", which included a methodology for projecting a hemisphere on a plane, .
By age 27, he had written a book called "Chronology" which referred to other work he had completed (now lost) that included one book about the astrolabe, one about the decimal system, four about astrology, and two about history.
He calculated the radius of the Earth to be 6,339.6 km (this result was replicated in the West in the 16th century).
Al-Biruni's contributions to mathematics include:
theoretical and practical arithmetic
summation of series
the rule of three
method of solving algebraic equations
trisection of the angle