Section 1.4 Five-Point Geometry
¶A different geometric model for incidence geometry is shown in Figure 1.4.1. Before reading further, ask yourself how the five-point geometry differs from the four-point geometry
Parallel lines.
Definition 1.4.2.
Two lines are parallel if they have no points in common. Lines that are not parallel intersect at their common point(s).
How many lines are there in the four-point geometry that contain the point \(D\) and are parallel to the line \(AB\text{?}\)
How many lines are there in the five-point geometry that contain the point \(D\) and are parallel to the line \(AB\text{?}\)