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Math Help - Do you know??

  1. #1
    Member
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    Jan 2009
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    Ontario Canada
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    Do you know??

    IF endpoints A(-7-1) and B(5,5)

    How do you determine the equation of the circle passing through AB.

    Need help with this, I can fiqure this out. Which equation do I use and what would the answer be.
    Thanks for your help in advance.
    Joanne
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  2. #2
    Senior Member mollymcf2009's Avatar
    Joined
    Jan 2009
    From
    Charleston, SC
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    Hello bradycat!

    You can first use the mid-point formula to find the center of the circle:

    midpoint formula says:
    \frac{x_1+x_2)}{2} = h (x coordinate of center of circle)
    and you do the same for your k (y coordinate) with the y coordinates of the given points.

    So for your circle:

    \frac{-7+5}{2} = h

    \frac{-1+5}{2} = k

    So the coordinate of the center of your circle are:
    (h,k) or (-1,2)

    Using that, see if you can figure out the standard form equation for the circle.

    Good Luck!
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