Answer
A circle with the center of $(0;0)$ and the radius of $3$
Work Step by Step
The equation of a circle with the center of $(0;0)$ and the radius of $r$ is:
$x^2+y^2=r^2$
As r is a positive number, and $r^2=9$ the radius of the circle equals to 3.
The equation is a circle with the center of $(0;0)$ and the radius of $3$
