We have to find the equation of a circunference with:
As it is a circunference that passes through a point, we know that the distance between the center and the point must be the radius, as all points in a circunference are at the same distance from the center.
We will find then the radius, by calculating the distance:
Now, this means that the radius is √90.
We use the standard form for the equation of a circle:
where (h,k) is the center of the circle. In this case,
And replacing, we obtain that the equation of the circle is: