# Category:Harmonic Pencils

Jump to navigation
Jump to search

This category contains results about **Harmonic Pencils**.

Definitions specific to this category can be found in Definitions/Harmonic Pencils.

Let $A$ and $B$ be points on a straight line.

Let $P$ and $Q$ lie on $AB$ such that $\tuple {AB, PQ}$ is a harmonic range.

Let $O$ be a point which is not on the straight line $AB$.

Then the pencil $\map O {AB, PQ}$ formed by joining $O$ to the four points $A$, $B$, $P$ and $Q$ is said to be a **harmonic pencil**.

*This category currently contains no pages or media.*