What do President James Garfield and Pythagoras have in common? They were both lovers of mathematics, and in 1876, James Garfield constructed an original proof of the Pythagorean theorem. "Constructing Pythagoras," a hands-on investigation, challenges your students to derive the Pythagorean theorem (a2+ b2= c2) using the same proof as the USA's twentieth president, James Garfield.