This mathematician is named Pythagoras. He was the mathematician who discovered in what relation are the sides, angles, and length of the sides of a triangle. Today this idea is still being used in mathematics and represents one of the foundations in geometry that we use all around.
Euclid, the Greek mathematician wrote the most definitive text on geometry, is still referred to today. Euclid was considered as the “Father of Geometry”, and was known to be a great mathematician