| Sci & Tech Chronology: In the year 420 bce |
Mathematics
Hippias of Elis [b. Elis, Greece, c. 460 bce, d. c. 400 bce] discovers the curve called the quadratrix, which can be used to trisect an angle (and to square a circle, although Hippias probably did not know this). The quadratrix is the first curve known that is not a part of a straight line (mathematicians call straight lines "curves") or a circle and that cannot be constructed with straightedge and compass. See also 431 bce Mathematics; 240 bce Mathematics.
| Wikipedia: 420s BC |
| Millennium: | 1st millennium BC |
| Centuries: | 6th century BC – 5th century BC – 4th century BC |
| Decades: | 450s BC 440s BC 430s BC – 420s BC – 410s BC 400s BC 390s BC |
| Years: | 429 BC 428 BC 427 BC 426 BC 425 BC 424 BC 423 BC 422 BC 421 BC 420 BC |
| Categories: | Births – Deaths – Architecture Establishments – Disestablishments |
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 | Sci & Tech Chronology. History of Science and Technology, edited by Bryan Bunch and Alexander Hellemans. Copyright © 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved. Read more |
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