Essential Understanding
 You can use trigonometry to find the area of a regular
polygon
 You can use trig to find the area of a triangle when you
know the length of two sides and the included angle.
 Students will be able to find areas of regular polygons
and triangles using trigonometry.
Find the Area of the
Nonagon
 What is the area of a regular pentagon with 4in sides?
Round your answer to the nearest square 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?
Finding Area
 Suppose you want to find the area of a triangle. What
formula could you come up with to find the area of
any triangle using a trig function
 sinA = h/c
 h = c sinA
 A = ½(bc)sinA
What is the area of the
triangle
What is the area of the
Triangle?
Homework
 Pg. 646
 #6 – 28 even, 36, 45 – 47
 16 problems