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3.6 Angles in Polygons
Learning Targets:
• Find the sum of the interior and exterior angles in polygons.
• Find each interior/exterior angle in regular polygons.
• Work backwards from the angles to find the number of sides.
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What is a regular polygon?
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concave
convex
unless specifically stated, we will always use convex polygons
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Examine the regular polygons. Find the measure of each interior angle (remember­regular means they are all the same).
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Formulas
Sum of the interior angles: Sum of the exterior angles: ***To find each interior/exterior angle:
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Practice.
1. Find the sum of the interior angles of a 23­gon.
2. Find each interior angle of a regular dodecagon.
3. Find the sum of the exterior angles of an octagon.
4. Find each exterior angle of a regular dodecagon.
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