1. 10-3 Areas of Regular Polygons

2. Definitions
Center of a regular polygon  the center of the circumscribed circle.
Radius of a regular polygon  the distance from the center to a vertex. All radii of a figure are congruent.
Central angle of a regular polygon  an angle formed by two radii drawn to consecutive vertices. All central angles are congruent.
Apothem of a regular polygon  the perpendicular distance from the center of the polygon to a side.
Every apothem of a figure is congruent

5. Theorem
The area of a regular polygon is equal to half the product of the apothem and the perimeter.
A= ½ aP
Apothems are going to be found using special right triangles, and sine, cosine, tangent functions.

7. Find the area of a regular pentagon with perimeter of 40 centimeters.

8. Find the area of a regular octagon with a perimeter of 72 inches.

9. Find the area of a regular hexagon with apothem of 9.

10. Find the area of a regular polygon with 11 sides inscribed in a circle with a radius of 12.