## Prealgebra (7th Edition)

$\approx$56.52 miles
The formula for circumference of a circle is C = 2$\pi$r, where $\pi$ $\approx$ 3.14 and r is the radius. In this problem, the radius is given to be 9 miles. Therefore, plug 9 into the equation for "r" and then solve. See work below.