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5 Tutorials that teach Ballparking the Area of a Circle
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Ballparking the Area of a Circle

Ballparking the Area of a Circle

Author: Graham Pardun

This lesson explains how triangles and parallelograms can be used to estimate the area of a circle.

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Pretend that we don't know the value of PI. Pretend that we don't know that the area of the circle is PI times the radius squared. How are we going to figure out the area anyway? Check this out: You can put six equilateral triangles inside of a circle and get a rough estimate for the circle's area using a genius hack!