How would you write the name of a segment differently than the name of a line

 A line segment is represented (written) using letters for the start point and the end point, as in QR:  QR is the line segment connecting Q to R.  This is the most common case.

Expecially when we're not talking about points on a given line, a line can be refered to by any arbitrary name, such as "line f."

Check the internet ok that will