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The Pythagorean Theorem is one of the most popular to prove by mathematicians, and there are many proofs available (including one from James Garfield).

What's the most elegant proof?

My favorite is this graphical one:

alt text

According to cut-the-knot:

Loomis (pp. 49-50) mentions that the proof "was devised by Maurice Laisnez, a high school boy, in the Junior-Senior High School of South Bend, Ind., and sent to me, May 16, 1939, by his class teacher, Wilson Thornton."

The proof has been published by Rufus Isaac in Mathematics Magazine, Vol. 48 (1975), p. 198.

  • 11
    Possibly subjective2010-07-27
  • 1
    the question title should be edited to avoid an overly subjective question and reflect the real intent of the question.2010-07-27
  • 0
    @Katie: Any suggestions? I think that I will just make it community wiki...2010-07-27
  • 3
    rather than "most elegant," maybe just do "Different Proofs of the Pythagorean Theorem" or something...same effect, less subjective.2010-07-27
  • 0
    AFAIK this demonstration was known by the Indian mathematician of XII century Bhāskara.2010-07-27

17 Answers 17