There is no ray symbol in the fourth grade mathematics ray knowledge, only the name of the ray. In the knowledge of line segments in the fourth grade, line segments, straight lines and rays all belong to the category of lines, and they are all represented by concrete lines, indicating that there are no fixed mathematical symbols, only names. For example, it is often expressed in the form of "ray ab", in which ab is only used as a name.

Definition of ray name:

A ray can be represented by an endpoint and another point on the ray. The letter of the end point (starting point) is written in front and cannot be changed. The endpoint of the ray is a, and the other point is b, that is the ray AB. The endpoint of the ray is b, and the other point is a, that is the ray BA. Name two endpoints of a line segment with capital letters. One endpoint is A and the other endpoint is B, then this line segment is AB.