The basic equation for a circle is:

        (x – h)2 + (y – k)2 = r2


Where  (h, k) is the point that locates the center of the circle and r is the radius.

If we locate the center at the origin of our coordinate axes:

    x2 + y2 = r2

If we have a circle with origin of (4,0) and a 2 inch radius, write the equation for the circle.

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