The general equation for a circle is:
[tex](x-h)^2+(y-k)^2=r^2[/tex]
Where the center is (h,k) and the radius is r.
The equation we are given is:
[tex](x-2)^2+(y+3)^2=80[/tex]
From this, the center is (2,-3), and the radius is [tex]\sqrt{80}[/tex], or [tex]4\sqrt{5}[/tex].
Let me know if you have any questions, thanks!
