Answer:
arc = 7 pi
Explanation:
The length of the arc is circumference
C = 2 * pi *r
C = 2 * pi *4
C = 8 pi
A circle is 360 degrees. The arc is 315 degrees
The arc is 315/360 of the circle, that is 7/8 of the circle, so it will be 7/8 of the circumference
7/8C = 7/8 (8pi)
arc = 7 pi