The formula for the equation of a circle is (x – h)^2+ (y – k)^2 = r^2, where (h, k) represents the coordinates of the center of the circle, and r represents the radius of the circle.
where (x1, y1) is the coordinate of the center of the circle and r is its radius. In this case, the center is at (3, 1) and its radius is r = 6. Therefore, we write its equation as