How did the fourteenth amendment effectively nullify the dred scott decision of 1857?

First, take a look at the Dred Scott decision. In brief it says: If you came into the USA as a slave, you and your descendants are not American citizens. Also it says that the federal government can not regulate slavery in any new states that joined the United States. Now take a look at the fourteenth amendment: It consists of 4 sections. Section 1: If you're born in the United States, or become a naturalized citizen, you are a citizen of the United States. That right there nullifies the Dred Scott decision. Section 2: The number of people in the state for the purposes of determining representatives is the population of the state. This section modifies Article 1, Section 2 of the Constitution of the United States and gets rid of three fifths clause towards the counting of slaves. Section 3: Basically, says that those who rebelled against the United States during the civil war can't be an elected official unless Congress forgives them with a two thirds majority vote. Section 4: The United States is not liable for any expenses incurred by the rebelling states. We won't pay for your injured, and we won't pay for the value of the slaves we made illegal. So in conclusion, the fourteenth amendment banned slavery in the United States. So the issue of slavery addressed by the Dred Scott case became null and void.

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