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Circle conditions

  1. Mar 16, 2010 #1
    the general equation of a circle has 3 constants , so it is said that 3 conditions , like 3 points (on the circle) are required to specify a circle , but , we require only the center and radius to specify a circle , so how many conditions are actually required ??
  2. jcsd
  3. Mar 16, 2010 #2


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    Homework Helper

    The center is two pieces of information, an x-coordinate and a y-coordinate, thus three total. If you have x-y coordinates of 3 points, you can write 3 equations with 3 unknowns and solve for the radius and the coordinates of the center.

    See this thread:

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