Work Step by Step
Recall the equation for a circle with center $(h,k)$ and radius $r$: $(x-h)^2+(y-k)^2=r^2$ We have $ r^2=9$, so the radius is $$ r=3.$$
You can help us out by revising, improving and updating this answer.Update this answer
After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.