Answer: 18.85 kilometers
Explanation:
Arc length = 2πr∅°/360
= πr∅°/180°
Note, the diameter of the circle was given and not the radius.
Recall,
2r = d
r = d/2
= 18/2
= 9.
Now to find the length of the arc, use the formula above
Arc length = π x r x ∅°/180°
= 3.142 x 9 x 120°/180°
= 3,393.36/180°
= 18.85 kilometers.