First, determine the circumference (C) of the circle, the equation,
C = 2πr
Substituting the value or the radius,
C = 2π ( 4) = 8π
The arc length is the product of the circumference and the ratio between the subtended angle and 360. The mathematical expression is already,
S = (8π) x (72 / 360) = 0.8π
Thus, the arc is 0.80π.
