Ibrahim ibn Sinan was born in Bagdad (now located in Iraq) in 908 AD.  He was the grandson of Thabit ibn Qurra who translated many Greek  astronomical and mathematical works into Arabic. Ibrahim ibn Sinan studied geometry including tangents to circles, and the geometry of shadows, and the motion of the Sun.  He is considered the first Arab mathematician to think about mathematical philosophy.  He constructed an ellipse, parabola and hyperbola in On drawing the three conic sections.  Later in the manuscript he proves that the area of a segment of a parabola is four-thirds the area of the inscribed triangle.  Another work On the motions of the sun deals with the motion of the solar apogee, and has an analysis of the observations underlying Ptolemy's solar theory.

Author: Charles DeBoer

References:
http://www-history.mcs.st-and.ac.uk/~history/Mathematicians/Ibrahim.html
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