Answer:
18.8496 units (rounded o1ff to four decimal places)
Step-by-step explanation:
Arc length = 2 × π × r ×
r (radius) = 12 units ÷ 2 = 6 units
Central angle = 180°
For our semicircle, the arc length = 2 × π × 6 × = 18.8495559215 units
Or 18.8496 units (rounded o1ff to four decimal places)