Math CentralQuandaries & Queries


Question from Renata, a student:
A regular decagon is inscribed in a circle of diameter 36 feet.
Approximate the perimeter and area of the decagon.


If you join a vertex and the midpoint of an adjacent edge to the center you get a triangle.

What is its small angle?
Which edge do you know?
What are the other edges (use trig functions)?
What is the perimeter of the degagon?
What is the triangle's area?
What is the area of the decagon?

Good Hunting!


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