Image showing a vertical line with points C and points D
The ruler placement postulate says that if C is zero, the coordinate of D is negative.
The ruler placement postulate says that D cannot be set at zero.
The distance postulate says that there is a positive number called the distance between points C and D.
The ruler placement postulate says that either C or D can be set as zero.
The distance postulate says that there is a negative number called the distance between the points.
