Respuesta :

number of angles = number of sides

180 - 120 = 60 (calculating the exterior angle)

360 / 60 = 6

There are 6 sides.

Hope this helps! :)
formula for internal angles of a n gon is (n-2)180/n

so it has 120 on each of the angles

120=(n-2)180/n
times both sides by n
120n=180n-360
minus 180n both sides
-60n=-360
divide both sides by -60
n=6

6 sides