center (2,-8); r=9
center(0,0); r=4
center(-1,-1); r=1
I Will "Thumbs Up" Any or All Answers Since they Will Most Likely be Better Than Mine :)
-much appreciation! Natasza
You should rely on the formula of a circle that looks as $$(x - x_{center})^2 + (y - y_{center})^2 = R^2$$,
where the center of a circle has coordinates $$(x_{center}; y_{center})$$, any point of the coordinate system has coordinate $$(x ; y)$$, $$R$$ is radius. Good luck!