In mathematics, Pythagoras's theorem is a fundamental relation in geometry among the three sides of a right triangle. It states that the square of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the other two sides. The theorem can be written as an equation relating the lengths of the sides a, b and c, often called the "Pythagorean equation".
Not much accurate information is known about Pythagoras, since his life and works weren't recorded until centuries after his death.
Like many learned Greek researchers and philosophers, he probably traveled a lot when he was a young man, leaving his island of Samos for Egypt, Africa, and other parts surrounded by the Mediterranean.