The center of the circle is at (-1, 1). The radius is determined by the distance from the center to the highlighted point (6, -4). The distance = sqrt[(6+1)^2 + (-4-1)^2] = sqrt[49 + 25] = sqrt(74)
Therefore, the equation of the circle is:
(x + 1)^2 + (y - 1)^2 = 74