Which system of government is most likely to give you the greatest amount of personal freedoms?

Generally speaking, it would be a "democracy," or a "democratic republic" that is most likely to give you the greatest amount of personal freedoms, since the citizens are able to elect representatives in the legislature. 

Use the formula: (n-2)×180, where n is the number of sides(18-2)×180= 28800, now this is the full exterior angle of 18-gon so you divide it by 18.28800÷18=160