Where n= number of sides of the polygon. Interior angle =120∘.
(n−2)×180
n
=120 Get rid of the fraction by multiplying both sides by n. (n−2)×180=120×n n×180−2×180=120×n 180n−360=120×n 180n−120×n=360 60n=360 Divide both sides by 60 n=
360
60
Note: 1. The zero ( 0 ) at the end of 360 and 60 cancels each other 2. 6 divides itself 1 and 36,6 times n=6