If the diameter is 1/2 mile, that is 0.5 mile, then the radius is 0.25 -half of it!
the angular speed is theta/time, which means
w=theta/time
but another formula for it is Velocity*radians
w=velocity*radians
velocity is 180 mph and radians are (revolution/2

radius), that is:
w=180*(1/2

*0.25)
and if we calculate this, we have: w=114.59, which is the correct answer!