Question 980430
The method to solve can be this:


Find the line for JK.  Find the midpoint between J and K.  As a model form, call this midpoint  (u,v), and it is also the center of the circle.


Identify the slope, m for line JK.  Calculate another slope, {{{-1/m}}}.


Use the POINT-SLOPE form of equation of a line in the plane.
You will use it as {{{y-v=(-1/m)(x-u)}}};
perform arithmetic steps according to the number properties you know in order to put this equation into the general form that you want.