Question: 1. Show that the sum of the interior angles of any n-gon (a polygon with n sides) is π(n - 2). Notice that such polygons may be wildly irregular and even non convex.
2. Write the equation
1 + 3 + 6 + 10 +. . . . +(n(n + 1)/2) = (n(n + 1)(n + 2)/6)
using summation notation. Prove that the equation is true for all positive integers n by using induction.