Eyeballing it, it looks like the center is (2,4), two to the right, four up.
Let's say the minimum point on the circle is (2,1). So a radius is the distance from the center to there. It's a vertical line, 3 units in length.
We plug into the equation
![(x-2)^2 + (y - 4)^2 = 3^2](https://img.qammunity.org/2019/formulas/mathematics/middle-school/kgz9gfskgh67gdw8wxdf0x2g21pm3ni3op.png)
Final answer:
![(x-2)^2 + (y - 4)^2 = 9](https://img.qammunity.org/2019/formulas/mathematics/middle-school/r9yktf87fik615rj9z0nkcogmgh4jgcz1j.png)