For this case, what we must do is find three times the perimeter of the figure.
The length of the arch is given by:
Where,
r: radius of the circle
alpha: central angle in radians
We have then:
Then, the perimeter of the figure is:
If David runs around the field three times, he covers a distance of 648 yards.
Answer is in the photo. I couldn't attach it here, but uploaded it to a file hosting. link below! Good Luck!
cutt.ly/kzH1l58