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Area of a regular polygon. 11-4. Definition. Regular polygon- a polygon that has congruent sides and interior angles. Center of a regular polygon. The center of the circle that can be circumscribed about the polygon. Radius of regular polygon.
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Definition • Regular polygon- a polygon that has congruent sides and interior angles
Center of a regular polygon • The center of the circle that can be circumscribed about the polygon.
Radius of regular polygon • The distance from the center of a regular polygon to a vertex.
Apothem • Apothem of a regular polygon-the distance from the center of the polygon to a side.
Area of a regular polygon • The area of a regular polygon is equal to half the product of the apothem and the perimeter
Example 4 7
Special case: hexagon Since the interior angles of a hexagon are 120, the angle formed by a radius and a side is 60, so a 30-60-90 triangle is formed
Special case: hexagon 30 60
Hexagon • Radius = side • apothem = * side
Apothem, Side and Radius • The apothem bisects the side • If given any 2 of apothem, side or radius,use Pythagorean theorem to find third.
Example 13 10