Answer:
The equation would be x^2 + y^2 = 9
Step-by-step explanation:
In order to find this, start with the base form of the circle.
(x - h)^2 + (y - k)^2 = r^2
Now we input the center as (h, k).
(x - 0)^2 + (y - 0)^2 = r^2
x^2 + y^2 = r^2
Now we can input the radius of 3 in for r
x^2 + y^2 = 3^2
x^2 + y^2 = 9
