Respuesta :

sum of interior angles of polygon = (n - 2) x 180
in this case n = 6
so (6 - 2 ) x 180 = 4  x 180 = 720

x - 60 + x - 40 + 130 + 120 + 110 + x - 20 = 720
3x + 240 = 720
3x = 480
  x = 160

m<F = x - 20 = 160 - 20 = 140

answer
<F = 140°