Question 750706
since our two lines are parallel, the circle's diameter must be 6-1=5 (and so r=5/2)

This means that the x-coordinate of the center must 1+5/2=7/2

Next we can write:

{{{(x-7/2)^2+(y-k)^2=(5/2)^2}}}

after solving we determine that k=0.

therefore...

{{{(x-7/2)^2+y^2=(5/2)^2}}}