How to intersect a fixed-length line perfectly between two differently angled lines

[sean.swiatek]

Something I've often found myself needing to do is place a line or object of fixed length so that it intersects on both ends perfectly between two other differently angled lines (reference image shows red line is fixed length). If I drag the red line in a direction to try and get close, while snapping it to one of the lines, the intersection at the other end is never perfectly touching the other line. Any help is greatly appreciated.

[john.uhden]

@JBerns 

My opinion is that any function you write that creates or modifies entities MUST have an error handler and Undo controls.  You will note that almost all my command functions invoke a dummy command whose purpose is to prevent that extraneous AutoCAD prompt that you often see when a function ends.  It's an anomaly that one or more of us here discovered decades ago.  If no one else speaks up I'll take full credit.  😇

[john.uhden]

@sean.swiatek 

Then feel free to hit that "Accept" button at the bottom so that others know the problem has a solution.

That was kinda fun not using any ActiveX functions (like the old days).