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Math Help - πr2 = 21

  1. #1
    mezzie
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    πr2 = 21

    i have no idea how to solvethis wud sum1 plz help me!

    πr2 = 21

    pi x r"2" = 21
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  2. #2
    Grand Panjandrum
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    Quote Originally Posted by mezzie View Post
    i have no idea how to solvethis wud sum1 plz help me!

    πr2 = 21

    pi x r"2" = 21
    What is the question? Is it rearrange this to something like r= some expression possibly in terms of 21 and pi ...?

    Divide both sides by \pi to get:

    r^2=\frac{21}{\pi}

    Now take the sqruare root (we want the positive root because r is presumably the radius of a circle):

    r=\sqrt{\frac{21}{\pi}}

    RonL
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