Pythagoras was a Greek conceptual philosopher who is widely considered one of the greatest mathematicians of all time. His best known theorem is the formula for right angle triangles, in which 'the sum of the squares of the lengths of the right angle sides is equal to the square of the hypotenuse (the angle which isn't part of the right angle). This is one of the primary theorems of modern geometry, used widely in structural measurement, architecture, and even TV screen measurements. The hypotenuse measurement is particularly important for accurately predicting and measuring distances between corners based on right angles.