Proposition: Prop. 11.04: Line Perpendicular to Two Intersecting Lines is Perpendicular to their Plane
Euclid's Formulation
If a straight line is set up at right angles to two straight lines cutting one another, at the common point of section, then it will also be at right angles to the plane (passing) through them (both).
* For let some straight line $EF$ have (been) set up at right angles to two straight lines, $AB$ and $CD$, cutting one another at point $E$, at $E$.
* I say that $EF$ is also at right angles to the plane (passing) through $AB$ and $CD$.
Modern Formulation
(not yet contributed)
Table of Contents
Proofs: 1
Mentioned in:
Proofs: 1 2 3 4 5 6
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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