Proving ?R² Using Chains, a Ruler, and Sixty Seconds

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In this brief video, Minute Physics shows a visual proof demonstrating why ?R² gets you the area of a circle. By using various lengths of chain laid into a circular shape, you can make a triangle from the circle -- and from there it's a hop, skip, and a trigonometry jump to proof of your circle's area. Check it:

As Minute Physics explains in the YouTube video description, this video is based on a paper by Russell Jay Hendel of Dowling College: Proof Without Words: Area of a Disk is ?R² (PDF link).

See also: Explaining E=mc² Using a Radioactive Space Cat.

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June 27, 2012 - 8:57am
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