Euclid:Proposition/XIV/4

Proposition

In the words of Hypsicles of Alexandria:

If $ABC$ be an equilateral triangle in a circle, $D$ the centre, and $DE$ perpendicular to $BC$,
$30 BC . DE =$ (surface of icosahedron).

(The Elements: Book $\text{XIV}$: )


Sources

  • 1926: Sir Thomas L. Heath: Euclid: The Thirteen Books of The Elements: Volume 3 (2nd ed.) ... (previous) ... (next): The Contents of the So-Called Book $\text{XIV}$. By Hypsicles
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