Question

How do you identify the center and the radius of the circle with equation `x^2 + (y - 5)^2= 9`?

Answer 1

Please see the explanation.

Explanation:

If you write it in this form:

`(x - 0)^2 + (y - 5)^2 = 3^2`

And then compare it with the standard form:

`(x - h)^2 + (y - k)^2 = r^2`

where `(h,k)` is the center and `r` is the radius.

It is easy to observe that the center is `(0,5)` and the radius is `3`.