Subject:
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Re: Math problem, please help!
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Newsgroups:
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lugnet.cad
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Date:
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Mon, 4 Nov 2002 00:54:45 GMT
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Viewed:
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402 times
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Math can be broken down as follows.
origin is x0, y0. radius is r.
we know x0=-310. y0, r are unknowns.
general equation for a circle:
(x-x0)^2 + (y-y0)^2 = r^2
from point one, we know
(-50-y0)^2 = r^2.
from point two, we know
(-30.37- -310)^2 + (-120.11 - y0)^2 = r^2
setting these two equations equal to each other we get:
2500+100y0 + y0^2 = 78192.94 + 14426.41 + 240.22y0 + y0^2
this is a simple linear equation to solve:
-90119.35 = 140.22 y0
y0 = -642.6997
plugging into equation #1 (-50 + 642.6997)^2 = r^2, giving r=592.6997
checking our work for equation #2
(-30.37 - -310)^2 + (-120.11 - -642.6997)^2 =
279.63^2 + 522.5897^2 = 351292.937500
origin (-310, -642.6997)
radius: 592.6997
On Sunday, November 3, 2002, at 02:15 PM, Tore Eriksson wrote:
> I have a circle with unknown radius.
>
> Origo is at x=-310, y=unknown.
> One known point is x=-310, y=-50, that's the top value of y.
> The other known point is at x=-30.37, y=-120.11
>
> I want to know the radius of the circle. It could be somewhere between
> 400
> and 700 units. Anybody?
>
>
> TIA,
> /Tore
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 | | Math problem, please help!
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| I have a circle with unknown radius. Origo is at x=-310, y=unknown. One known point is x=-310, y=-50, that's the top value of y. The other known point is at x=-30.37, y=-120.11 I want to know the radius of the circle. It could be somewhere between (...) (22 years ago, 4-Nov-02, to lugnet.cad)
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