Pythagoras was born on an island called Samos. When he was young, he engaged in many different travels, including Egypt and other locations that piqued his interest in gaining more knowledge. He is most widely known for the Pythagorean theorem, which states that "a right-angled triangle the area of the square on the hypotenuse is equal to the sum of the areas of the squares of the other two sides," in other words, A2 + B2=C2.
This theorem is believed to have been used by the ancient Babylonians and the Indians, although their use of this is based on evidence of the understanding of the principle, and not on recorded writings.