
Approximating Pi with Polygons and Algebra
Hard
Can you pin down the value of pi by wrapping polygons tighter and tighter around a circle? You start with a square drawn around a circle of radius 1. Then you double the number of sides to 8, then 16, and so on. Each polygon's perimeter gets closer to the circle's circumference.
This process produces a recursive equation that approaches pi from above. The project also shows that this upper-bound formula matches a famous expression published by Francois Viete centuries ago.
Finally you derive an algebraic polynomial where one root is pi itself. The other roots are new numbers called the Pi Associates, whose properties remain unexplored.
Hypothesis
The hypothesis is that Pi can be derived from an Algebraic Polynomial.
Method & Materials
You will use regular circumscribed polygons about circle of radius 1 to derive an upperbound expression for Pi. You will start from a square and construct an 8-sided regular polygon, doubling the number of sides. This procedure can be repeated endlessly doubling the sides of the polygon with every step.
You will need regular polygons, a circle of radius 1, and a calculator.
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See what’s includedResults
Through this project, we have discovered the upperbound recursive equation for Pi and the Pi Associates. We have also shown that François Viete's expression for Pi is equivalent to my last year's lowerbound expression for Pi.
Why do this project?
This science project is so interesting and unique because it involves discovering the mystery of Pi and the Pi Associates.
Also Consider
Experiment variations to consider include using different shapes of polygons and different radii of circles.
Full project details
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