**Abu Raihan Al-Biruni** (

September 15,

973 -

December 13,

1048) was a

Muslim mathematician,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. 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.
- Calculated the radius of the Earth to be 6339.6 km (this result was replicated in the West in the 16th century).

Al-Biruni's contributions to mathematics include:

- theoretical and practical arithmatic
- summation of series
- combinatorial analysis
- the rule of three
- irrational numbers
- ratio theory
- algebraic definitions
- method of solving algebraic equations
- geometry
- Archimedes' theorems
- trisection of the angle

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