Posted by Rallaz on Dec 28, 2012; 2:03pm
URL: https://forum.librecad.org/Adding-and-joining-a-parallel-line-tp5707376p5707382.html

Attached your file with the "arcs" extendeds
12x15x8b.zip

what you look is "Modify->Trim" (really is trim/extend)
the problem is that it does not work with polylines.
Yes, you do not have arcs in your drawing, both are pieces
of line (joined as polyline) creating an arc approximation