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popjump
Can someone describe one useful application of the pythagorean theorem?
how far from the wall you need to setup a ladder to reach the top of the roof
http://betterexplained.com/articles/surprising-uses-of-the-pythagorean-theorem/
http://gwenellenmorett.suite101.com/the-pythagorean-theorem-a21010
determining irrational lengths without error induced by measurement