Measure distance of line parallel to vertical axis and use measurement to establish line in horizontal plane

use tape to measure distance then establish guide in reference to a different axis

Is that a question?

Please ask a question and share a screenshot of what you are trying to accomplish. It might be that you can just measure the line you’re interested in or select it and look at Entity Info. Then draw a new line the same length.

how would i get a screenshot to you

and how do I do that (ie a screenshot)?

Is this what you are trying to accomplish:

The distance between two vertical guides measured at a certain height?
Inferencing (constrained “On Face”) to a horizontal face keeps you drawing on its plane

On my window computer I use a utility for screen capture.

With this tool, I can selex=ct a rectangular area on the screen then I save the capture where I need it, like the desktop, for example. Then I can attach this file to a post in this forum.