Respuesta :

s = (angle/360)*2*pi*r
s = (t/360)*2*pi*r
s = (2t/360)*pi*r
s = (t/180)*pi*r
now plug in s = 12 to get
12 = (t/180)*pi*r
now solve for the angle t to get
t = 180*12/(pi*r)
t = 2160/(pi*r)