Polygon interior angle sum patterns.

Use this applet to study patterns with interior angle sums of polygons.

Start with the green polygon.

#1

How many sides does the green polygon have? What type of polygon is it?

Find the sum of the interior angles of the green polygon. Does it stay the same or change when you move the vertices?

Now look at the red polygon.

How many sides does the red polygon have? What type of polygon is it?

Find the sum of the interior angles of the red polygon. Does it stay the same or change when you move the vertices?

Next look at the purple polygon.

How many sides does the purple polygon have? What type of polygon is it?

Find the sum of the interior angles of the purple polygon. Does it stay the same or change when you move the vertices?

Finally look at the blue polygon.

How many sides does the blue polygon have? What type of polygon is it?

Find the sum of the interior angles of the blue polygon. Does it stay the same or change when you move the vertices?

Putting it all together

Each time you add an extra side to the polygon, what happens to the sum of the interior angles? Be as specific as possible.

What connection can you find between the interior angles of triangles and the interior angles of other polygons?