Angle measures in polygons are affected by the number of sides the polygon has.

To explore the relationship of sides and angles of a polygon, click on the picture and follow the directions below. This will open in a new webpage.

You can change the number of sides of the polygon by clicking on the gray words “more” or “less” to the right of the polygon.

Select three sides, a triangle, and then use your notes to record your answers to the following questions.

1. What happens when you click the word “less” over and over?
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The number of sides will never be less than three.

2. Why do you think the number of sides will not go below 3?
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A polygon must have at least three sides.  If it had only two sides, they would have to either be intersecting or parallel lines, which do not form a polygon.

3. Now, begin increasing the number of sides of the polygon by clicking the word “more”.  What do you notice about the measure of each angle?
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The angles increase in size.

4. What do you notice about the sum of the measures of the angles?
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The sums increase.