Happy Monday!
Warm­Up:
How many sides do the following shapes have?
1. Hexagon
4. Pentagon
2. Decagon 5. Dodecagon
3. Heptagon
6. Nonagon
Regular Polygon:
What other shapes do you see within the polygon?
How might this help me find the area?
What information do I need?
Parts of a regular polygon:
Ex 1) Find the area of the regular heptagon.
16 m
15.4 m
Ex 2) Find the side of the regular pentagon if the apothem is 2.75 ft and the area is 27.5 ft2.
Ex 3) Find the area.
Steps:
1. Split shape into triangles. Find central angle and angle in right triangle.
8 in
2. Use special triangles or SohCahToa to find the needed side(s) of the triangle.
3. Find area of one triangle and multiply by the number of triangles.
Ex 4) Find the area.
12 in