Definition of a ray

 

 A ray (or half-line) is a part of a line consisting of the given point and all points lying on one side of it.

Any point on a line divides the line into two rays.

Definition of a ray

A ray (or half-line)

Designation of rays

Rays (or half-lines) the same as lines are designated by lowercase Latin letters: ray a or ray b.

A half-line (or ray) is also designated by two points: the initial point and another point belonging to the half-line. In doing so, the initial point is placed in the first place. In such case, uppercase letters are placed: ray AB or ray CD.

Designation of rays

The ray АВ and the half-line CD

Drawing a ray

 

Step 1

 

Draw line a.

 

Step 2

 

Mark point O on line a.

This point O divides line a into two parts, each of which is called a ray emanating from point O (one of the rays generated is marked in blue, the other in green).

Point O is called the origin of each of the rays.

Drawing a ray. Step 1

Drawing a ray. Step 1

 

 

Drawing a ray

Drawing a ray. Step 2