Answer:
p = 9π + 18 miles Exact answer
p = 46.26 miles decimal approximation
Explanation:
The whole circumference of a circle is
c = 2πr
Half a circle's circumference plus the diameter would be the semicircle's perimeter
p = (1/2)2πr + 2r
p = πr + 18
p = 9π + 18 miles Exact answer
p = 3.14 * 9 + 18
p = 46.26 miles decimal approximation