Only one straight line can be drawn through two points; two points determine a straight line.

A straight line is the shortest line connecting two points in a plane.

A line segment can be bisected at only one point.

If two lines intersect, four angles are formed at the point of intersection. An angle has only one bisector

Two lines in the same plane either intersect or are parallel.

All straight angles are congruent.

All right angles are congruent as they have the same measure.

In a plane, only one line can be drawn through a point perpendicular to a line.