In principle a proof of the Pythagorean theorem
Socrates might have added, speaking to his friend Menon, that the boy has just delivered in principle a proof of the Pythagorean theorem. The theorem states that the squares over the small sides of a right triangle, when added together, are equal in area to the square over the long side. In the case at hand, Asquare is the size of the original square, likewise Bsquare. The two added together, add up to Csquare that is twice as big. The boy proved Pythagorean theorem. Of course, the proof, in this particular case is simple, as A and B are of equal length.
