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The Fencing Problem - semi-circles watch

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    Can anyone tell me if it is possible to work out how the fencing would have to be distributed to make a semi-circle (ie. how long the curved edge would be, and how long the straight edge would be)
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    (Original post by elfbadger)
    Can anyone tell me if it is possible to work out how the fencing would have to be distributed to make a semi-circle (ie. how long the curved edge would be, and how long the straight edge would be)
    The curved bit would have to be pi/2 times the length of the straight bit.

    Ben
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    (Original post by Ben.S.)
    The curved bit would have to be pi/2 times the length of the straight bit.

    Ben
    So in other words, with 1000 metres of fence, it would be 1000/(pi/2) to work out the length of the straight? Or does what I just said make no sense?
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    If you mean the perimeter of a semicircle:

    P=((pi)d/2)+d, where d=diameter
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    So how would I work out the diameter from the perimeter?
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    (Original post by elfbadger)
    So in other words, with 1000 metres of fence, it would be 1000/(pi/2) to work out the length of the straight? Or does what I just said make no sense?
    The whole fence must be of length x[1+(pi/2)]. You can find the lengths of either part of a semicircle from that. So, with a 1000m fence;

    x = 1000/[1+(pi/2)]
    Straight length = x
    Curved length = (pi/2)x

    Ben
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    (Original post by XTinaA)
    If you mean the perimeter of a semicircle:

    P=((pi)d/2)+d, where d=diameter
    To get d:

    P=((pi)d/2)+d
    =d((pi)/2+1)
    d=P/(pi/2+1) (edited error, cheers Ben S)

    I think...
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    Thanks, I got the grasp of it (eventually) from what Ben said.
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    By the way, you're wonderful, wonderful people.
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    (Original post by XTinaA)
    To get d:

    P=((pi)d/2)+d
    =d((pi)/2+1)
    d=(pi/2+1)/P

    I think...
    You've got your division the wrong way round!

    Ben
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    (Original post by Ben.S.)
    You've got your division the wrong way round!

    Ben
    Guuh! Oh yeah. Youse know what I mean...
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    Doesn't matter, you still know what you're talking about better than I do.
 
 
 
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