Download 10.5 Trig and Area.notebook

10.5 Trig and Area.notebook
January 16, 2014
Unit 7: Area
10.5 Trigonometry and Area
What is the area of a regular pentagon with 4 inch sides?
What is the area of a regular
octagon with 7.5 cm sides?
10.5 Trig and Area.notebook
January 16, 2014
Find the area of each to the nearest tenth.
1. decagon with side length 4 yd
2. nonagon with radius of 7 in
A tabletop has the shape of a regular decagon with a radius of 9.5 in. • What is the area of the tabletop to the nearest square inch?
• If the radius was doubled, how would the area change?
10.5 Trig and Area.notebook
January 16, 2014
Theorem 10­8 Area of a Triangle given SAS
Area = ½(side)(side) sin(angle)
side
e
le
sid
ang
c
A
b
Where does this formula come from?