Summarize the following:
The polygon can have any number of sides and can be regular or irregular. For example, you might want to find the sum of the interior angles of a hexagon, so you would draw a six-sided shape. Label this vertex A. A vertex is a point where two sides of a polygon meet. The lines should not cross. You should create a number of triangles. You do not have to draw lines to the adjacent vertices, since they are already connected by a side. For example, for a hexagon you should draw three lines, dividing the shape into 4 triangles. Since there are 180 degrees in a triangle, by multiplying the number of triangles in your polygon by 180, you can find the sum of the interior angles of your polygon. For example, since you divided your hexagon into 4 triangles, you would calculate 4180=720{\displaystyle 4 imes 180=720} to find a total of 720 degrees in the interior of your polygon.
Draw the polygon whose angles you need to sum. Choose one vertex. Draw a straight line from Point A to each other vertex in the polygon. Multiply the number of triangles you created by 180.