The Pythagorean Theorem - Educational Outreach

2.8) Henry Perigal’s TombstoneHenry Perigal was an amateur mathematician andastronomer who spent most of his long life (1801-1898)near London, England. Perigal was an accountant by trade,but stargazing and mathematics was his passion. He was aFellow of the Royal Astronomical Society and treasurer ofthe Royal Meteorological Society. Found of geometricdissections, Perigal developed a novel proof of thePythagorean Theorem in 1830 based on a rather intricatedissection, one not as transparent to the casual observerwhen compared to some of the proofs from antiquity. Henrymust have considered his proof of the Pythagorean Theoremto be the crowning achievement of his life, for the diagramis chiseled on his tombstone, Figure 2.27. Notice the cleveruse of key letters found in his name: H, P, R, G, and L.PRHCGLALGBHRPAB 2 =AC 2 +CB 2DISCOVERED BY H.P.1830Figure 2.27: Diagram on Henry Perigal’s Tombstone61