if it's a tangent to the x and y axes, then the center of radius lies on the line y = x
so let the center of the circle be (xc,xc)
xc is the radius
perpendicular distance between center and tangent (which is the radius)
xc = |4xc + 3xc - 60| / 5 (equal radii)
5xc = |7xc - 60|
5xc = 7xc...