Answer
(a). $(h,k)=(0,2), r=2$.
(b). See graph.
(c). $(0,0),(0,4)$.
Work Step by Step
(a). $x^2+y^2-4y=0\longrightarrow (x)^2+(y-2)^2=4$, thus $(h,k)=(0,2), r=2$.
(b). See graph.
(c). For x-intercept(s), let $y=0$, we get $(0,0)$, for y-intercept(s), let $x=0$, we get $(0,2\pm2)$ or $(0,0),(0,4)$.
