The formula in getting the circumference of a circle is:
[tex]C=2\pi r[/tex]where r = length of the radius and π = 3.14159.
Since the radius is already given in the circle which is 9.9 km, let's use this value to replace "r" in the formula. Use 3.14159 to replace π as well.
[tex]C=2\times3.14159\times9.9km[/tex]Then, multiply.
[tex]C=62.203482km\approx62.2km[/tex]Hence, the circumference of the given circle is approximately 62.2 km.