Answer:
Step-by-step explanation:
Compare the equation to the standard form for the equation of a circle:
(x -h)² +(y -k)² = r² . . . . center (h, k), radius r
x² + y² = 9
We can see that h = k = 0, and r = √9 = 3.
The center is (0, 0), and the radius is 3.
