What was the effect of the dred scott decision?
a. congress could not prohibit slavery.
b. slavery was abolished in the south.
c. maine was admitted as a slave state.

None of these three were direct effects of the ruling of Dred Scott's case. This case proved that states where slavery was illegal had almost no power when it came to cases such as this. The state of Maryland had made slavery illegal, but there was still an inherent racial bias against blacks. The judge dismissed the case, and this proved that states had no real power over themselves when it came to the rights of other states.

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