Two On A Big Ocean The Story of the First Circumnavigation
of the Pacific Basin
in a Small Sailing Ship


      

Other Books by
Hal Roth
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Re: lv-ab: Question

From: (no name) (no email)
Date: Sun Mar 02 2003 - 23:28:05 EST

  • Next message: Jeff Bole: "Re: lv-ab: Question"

    Wow, its a bunch of years since I did this stuff, like 50!
    This may not be the simplest solution and I could have an error but this is
    what I came up with.
    Assume the length of the straight line is x
    Assume the height of the curve in the middle is y.
    Since I can't show superscripts here, squared is shown as ^2
    I get the radius of the circle as r = (x^2 + 4*y^2)/8*y
    So the total circumfrence is (pi*x^2 + 4*pi*y^2)/4*y
    The angle between sides of the whole pizza slice is ArcSin(x/r)
    = ArcSin{(4*x*y)/(x^2 + 4*y^2)}
    So the length of the arc is angle/360 * circumfrence
    = ArcSin{(4*x*y)/(x^2 + 4*y^2)} * (pi*x^2 + 4*pi*y^2)/1440*y
    Plug some actual numbers in and see if it comes close. If its wrong it will
    be radically wrong.

    Colin Foster,

    I have a geometry problem.

    Imagine two horizontal lines, one straight and one curved, a few inches
    long, sorta parallel with the ends of each line touching the other. Like
    you sliced a piece of the crust of a pizza off and the sliced-off piece is
    lying on the table.

    I know the length of the straight line that the knife cut, and I know the
    distance apart the lines are in the middle of the sliced off pizza crust,
    how do I find the length of the curved line?

    Norm

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