A-5 deals with patterns found in POLYGONS, which are two-dimensional (or “plane”) closed figures consisting of line segments (or lines) as sides. Triangles are polygons. So are quadrilaterals, pentagons, etc. Circles are not.

Guided Practice:

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1. Find the sum (total) of the interior angles of a 40-sided polygon (40-gon)

2. Find the measure of each angle of a regular 90-gon. (NOTE: A regular polygon is a polygon where every side has the same length and every angle has the same measure)

3. Find the measure of each exterior angle of a regular 45-gon. (NOTE: An exterior angle is the difference between 180 degrees and an interior angle. Basically, what makes up a straight line with the interior angle)