To draw a straight line perpendicular to a given infinite straight line from a given point which is not on it. * Let $AB$ be the given infinite straight line and $C$ the given point, which is not on ($AB$). * So it is required to draw a straight line perpendicular to the given infinite straight line $AB$ from the given point $C$, which is not on ($AB$).
Given an arbitrary straight line $AB$ and an arbitrary point $C$ not on the line, we may construct a perpendicular segment $\overline{CH}$ from the point to the line.
Proofs: 1
Definitions: 1 2
Proofs: 3 4 5 6 7 8 9 10 11 12
Propositions: 13 14 15
Sections: 16