Choose Create, Line, Parallel.
Line parallel ribbon bar
|Use this ribbon bar to create a line parallel to an existing line. Select an existing line and click a point in the graphics window to position the parallel line.
You can also use this ribbon bar to create a line parallel to a line and tangent to an arc by selecting an existing line and then an arc.
Although the parallel line is live, only the distance between it and the original line can be edited, not the line’s length. By default, the parallel line will be the same length as the original line. To set a different length for the parallel line, use the Analyze function’s Line Properties dialog box.
1 – Edit endpoint 1 (edits the distance between the lines)
F – Flip
D – Distance
T – Tangent (creates lines tangent to an arc)
P – Apply
O – OK (fixes live entity and exits function)