I'm making a spreadsheet that shows the circumcenter of a triangle
with the 3 points as input from the user. I can get the circumcenter
calculated no problem, but now I want to make 1 circle radiating from
the point the user has input that will also cross the circumcenter
point.

Say the point the user enters is 1,1 and the circumcenter is a 2,2. I
want a circle that's center is at 1,1 and crosses through point 2,2.

Any ideas?