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put this solution on YOUR website!If the diameter is 8.2, then the radius is simply half the diameter. So the radius is
Since the center is (4,5), this means that h=4 and k=5. Note: remember, the center of any circle is (h,k)

Start with the general equation of a circle

Plug in

,

(this is the center) and

Square 4.1 to get 16.81
So the equation of the circle with a center of (4,5) and a diameter of 8.2 units is