Length of an Arc Formula

Equation for calculate length of an arc is,

r = (h/2) + (w²/(8h))
C = 2 tan^-1(w/(2×(r-h)))
if(C < 0)
C = 360 + C
l = C × 2 Π r / 360

r = Radius of Arc
h = Height of Arc
w = Width of Arc
C = Center Angle of Arc
l = Length of Arc