Talk:Complementary angles

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Who first noticed this? I would've thought Euclid, but I was watching James Burke's The Day the Universe Changed and he mentioned it was a Greek named Tales (sp?).67.149.196.50 (talk) 13:11, 21 February 2010 (UTC)

That would be Thales, a Greek geometer who predated Euclid by several hundred years. I don't know if he was the first to prove the angles of a right triangle are complementary, but from the sophistication of his ideas it's clear that he would have known of this result. Robert Hiller (talk) 04:31, 18 May 2010 (UTC)