A horizontal line and a vertical line always intersect at right angles.
If the arms of an angle on the paper are increased, the angle increases.
If the arms of an angle on the paper are decreased, the angle decreases.
If line PQ ∥ line m, then line segment PQ ∥ line m.
Two parallel lines meet each other at some point.
Measures of ∠ABC and ∠CBA in Fig. 2.23 are the same.

Two line segments may intersect at two points.
Many lines can pass through two given points.
Only one line can pass through a given point.
Two angles can have exactly five points in common.