what is the radius and how do I know what it is?

Answer:
The results are:
Center: [tex](0, 10)[/tex]
Radius: [tex]4[/tex]
Step-by-step explanation:
-The center and radius from the equation of a circle is really easy to find, because from the equation, the center is [tex](h,k)[/tex] and the radius is [tex]r[/tex], so the center is [tex](0,10)[/tex], but to find the radius, you need to square root the simplified radius from the equation of the circle:
[tex](x-h)^2 + (y-k)^2 = r^2[/tex]
[tex]x^2 + ( y - 10)^2 = 16[/tex]
Center: [tex](0, 10)[/tex] Radius: [tex]4[/tex]