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Explore the fascinating realm of geometric construction as Mike Frost delves into the capabilities and limitations of using a straightedge and compass. Discover how to multiply and halve lengths, drop perpendiculars, and take square roots, while understanding what cannot be achieved—like angle trisection and cube roots. Dive into the construction of polygons, particularly focusing on the pentagon and the intriguing 17-gon, with references to Fermat primes and the contributions of Carl Friedrich Gauss and Paul Nahin's interpretations of Euler’s formula.
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17 Sides By Mike Frost
What Can You Construct with Straight Edge and Compass? Lengths can be multiplied
Square Roots can be taken But you can’t: Trisect an Angle or take Cube Roots
To construct a Polygon with a prime number of sides n, n must be a Fermat Prime, of the form: F0 = 3 Five known Fermat Primes N=0,1,2,3,4 F1 = 5 F2 = 17 F3 = 257 F4 = 65, 537 Carl Friedrich Gauss
Cos (2 π / 17) ... Cos (2 π / 3) = -0.5 Cos (2 π / 5) = (-1 + sqrt(5) ) / 4 Cos (2 π / 257) ?
...and Cos (2π/65,537) ??
The Biggest ConstructibleOdd-Numbered Polygon3 . 5 . 17 . 257 . 65537= 4 , 294 , 967 , 295 Sides