Proposition: Prop. 12.05: Sizes of Tetrahedra of Same Height are as Bases
Euclid's Formulation
Pyramids which are of the same height, and have triangular bases, are to one another as their bases.
* Let there be pyramids of the same height whose bases (are) the triangles $ABC$ and $DEF$, and apexes the points $G$ and $H$ (respectively).
* I say that as base $ABC$ is to base $DEF$, so pyramid $ABCG$ (is) to pyramid $DEFH$.
Modern Formulation
(not yet contributed)
Table of Contents
Proofs: 1
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Proofs: 1 2
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References
Adapted from (subject to copyright, with kind permission)
 Fitzpatrick, Richard: Euclid's "Elements of Geometry"
Adapted from CC BYSA 3.0 Sources:
 Prime.mover and others: "Pr∞fWiki", https://proofwiki.org/wiki/Main_Page, 2016