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Thread: polygon

  1. February 1st 2010, 01:53 PM #1
    sri340
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    polygon

    How many diagonals does a regular seven-sided polygon contain?
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  2. February 1st 2010, 08:28 PM #2
    Soroban
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    Hello, sri340!

    How many diagonals does a regular seven-sided polygon contain?

    Take the 7 vertices, 2 at a time: . _7C_2 \:=\:\frac{7!}{2!\,5!}
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  3. February 2nd 2010, 08:19 AM #3
    Opalg
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    Quote Originally Posted by Soroban View Post
    Hello, sri340!Take the 7 vertices, 2 at a time: . _7C_2 \:=\:\frac{7!}{2!\,5!}
    ... But if you take a "diagonal" to mean a line connecting two non-adjacent vertices then the answer will be less (14, in fact).
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