What is the sum of the angle measures in a 20 sided polygon?

Answer 1

The answer is 324 degrees. The general formula is (n-2)*180 degrees, where n=number of sides/vertices(both are same). But this is valid only for convex polygon (every internal angle is strictly less than 180 degrees & every line segment between two nonadjacent vertices of the polygon is strictly interior to the polygon except at its endpoints)