I want to extend an existing line by a distance in the same direction. That is, after the edit, I will have two line segments, both in the same direction with one point in common. A use case for this is a land survey where a straight line goes into the property of a different person, so the distance in one property is stated separately from the distance in the other property. I'm doing this interactively.
@GerardAshton While sketching the second segment, you can use the right-click context menu and use Distance:
Reference:
https://pro.arcgis.com/en/pro-app/latest/help/editing/trim-or-extend-an-unfinished-line.htm
https://pro.arcgis.com/en/pro-app/latest/help/editing/trim-a-polyline-feature.htm