Answer
C $\approx$ 25.12 km
Work Step by Step
C = 2 $\pi$r
where $\pi$is approximately 3.14, r is 4 km
What is the area if $\pi$ is approximately 3.14 and r is 4 km
Evaluate the formula by replacing $\pi$ with 3.14 , r with 4 km
C = 2 * 3.14 * 4 km
$\approx$ 25.12 km