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THALES, FOUNDER OF GREEK GEOMETRY (585 B.C.E.)
The birth of Greek astronomy has been attributed to Thales of Miletus. Thales brought from Egypt a number of fundamental geometric principles. Thales, an Ionian (western border of Asia Minor) who was active near the start of the sixth century bc has been credited with a number of geometric theorems. 1. A Circle is bisected by its diameter. 2. Angles at the base of any isosceles triangle are equal. 3. If two straight lines intersect the opposite angles formed are equal. 4. If two triangles have two angles and one side respectively equal, the triangles are equal in all respects. Thales was also well known for forecasting the solar eclipse, so he was also considered a scientist.
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This is timeline of mathematics through the ages