First we need to convert the given equation to standard form.
[tex] x^{2} + y^{2} -2y-99=0 \\  \\ 
 x^{2} + y^{2}-2(y)(1)=99 \\  \\ 
 x^{2} + y^{2}-2(y)(1)+1=99+1 \\  \\ 
 x^{2} + (y-1)^{2}=100   [/tex]
Comparing this equation to the standard equation of circle, we can write:
The center of the circle is (0, 1) and the radius of the given circle is 10