Answer:
Formula for the Arc length is given by:

As per the statement:
radius of circle(r) = 6 units
Angle (
) =
radian
Use conversion:

=

then;
substitute these given values we have;
Use value of


or

Simplify:

Therefore, the arc length of the arc substended in a circle with radius 6 units an angle of 7 pi/8 is 16.485 units