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Angle properties of polygons - 2nd Oct 2008

Today was the second of two lessons looking at the properties of polygons. We talked about the interior and exterior angles of polygons.

The sum of the interior angles of a polygon is the total of all the inside angles added together. You can find the sum of interior angles for both regular and irregular shapes.

The sum of the interior angles is found by dividing up the polygon into triangles from one vertex and then multiplying the number of triangles by 180° (the sum of the angles in a triangle).

Here are some examples:

We also looked at how we can find the size of one of the interior angles in a regular polygon. You cannot find the interior angle of an irregular polygon this way because the angles are different.

We looked at the following two methods. either can be used.