The total angel of any polygons is (n as the totap side of the polygon) (n - 2) x 180°
now we can substitute 120° into this formula (n - 2) x 180° / n = 120° (because we're calculating each angle from the polygon, so we need to divide the equation by n) (180n - 360) = 120n 180n - 120n = 360 60n = 360 n = 6 a 6 side polygon is hexagon.