Ibn Qurra's Pythagorean Theorem Proofs
Pythagorean theorem proofs by dissection
Arab polymath Thābit ibn Qurra revised an earlier translation of the Elements and translated several other Greek works from the times of Euclid to Ptolemy. He also produced two original proofs of the Pythagorean theorem as well a generalization of the theorem (which, while valid, was stated without proof).
Thābit ibn Qurra presented two original proofs of the Pythagorean theorem using a method of dissection which he called the method of reduction to triangles and rearrangement by juxtaposition. These proofs appeared in a letter to a friend written around around 850 CE and are preserved in the library of the Hagia Sophia Museum in Istanbul, Turkey.