First find we find the distance between the two points. Using the distance formula we get about 9. Now we know the radius is about 4.5. Next we need to the center. This is found by taking the mid point of the two given end points. We do this by averaging the x values for the x origin and the same for the y values. This gives us (1,2). Now put this into the formula. THE ANSWER IS (x-1)^2+(y-2)^2=20.25
