Answer:
The arc length is 9.75 pi units
Explanation:
Mathematically, we use the formula below to get the length of an arc
Length of an arc is;
theta/360 * 2 * pi * r
where theta is the central angle
for 3pi/4 ; let us convert to degrees
The degree measure is 180 degrees for pi
so 3pi/4 will be (3 * 180)/4 = 135 degrees
So we have the arc length as follows;
135/360 * 2 * pi * 13 = 9.75 pi unit