Answer:
2π miles
Step-by-step explanation:
2πr is the formula for the circumference of a circle.
Using that formula, the circumference for this circle is 8π.
Since the circle's full angle is 360°, we can use a ratio to find out how long the 45° arc is.
° : length
360 : 8π
9 : 0.4π
45 : 2π
The 45° is 2π mi long.