Answer:
4.71
Step-by-step explanation:
First you use the formula : C=2πr (this is the formula for the perimeter of a full circle)
The radius is half the length of a circle. Half of 3 is 1.5.
2 x π x 1.5 = 9.42
Now we divide answer by 2 since its only half a circle
9.42 / 2 = 4.71
