The equation of the circle is x^2 + y^2 = r^2, where r is the radius of the circle.
In this case, x^2 + y^2 = 121, so the radius is the square root of 121, which equals 11.
Therefore, the radius of the circle is 11.
The equation of the circle is x^2 + y^2 = r^2, where r is the radius of the circle.
In this case, x^2 + y^2 = 121, so the radius is the square root of 121, which equals 11.
Therefore, the radius of the circle is 11.