Though its roots are in geometry, the theorem universally attributed to Pythagoras has found its way into nearly every branch of science, pure or
applied. Well over four hundred proofs of it are known, and their number is still growing; the list includes an original proof by a future American president, another by twelve-year-old Albert Einstein, and still another by a young blind girl. Some of these proofs are breathtaking in their simplicity, while others are incredibly complex.