What is the angle sum for an eleven sided polygon?

Answer 1

The formula for finding the sum of the interior angles of a polygon is:

180 x (n - 2) where n = the number of sides.

This comes from knowing the following: Given a polygon of n sides, there are n - 2 triangles you can form by connecting a given vertice (point where two sides meet) to all other vertices of the polygon. The 180 in the formula is the sum of the angles in a triangle.

Therefore, the sum of the interior angles (or, as you put it, the angle sum) of your 11 sided figure would be:

180 x (11 - 2) = 180 x (9) = 1620 degrees.

Hope that answers your question and gets you on your way to figuring out other geometry problems.