Posted by Rallaz on Sep 18, 2011; 8:37am
URL: https://forum.librecad.org/feature-discussion-ID-3408426-tp4805930p4815616.html

For me you do complicated what is simple:

Option 1:
Modify->Move/Copy,
    select the line
    base point: endpoint of line
    target point: center of circle
    keep original (for copy)
Draw->Circle->Center,Radius,
    set radius to 70
    circle center: center of circle
Modify->Move/Copy,
    select the original circle
    base point: center original circle
    target point: intersection of auxiliary line and circle
    keep original (for copy)
Modify->Delete,
    select the aux circle (70u) & line copied).

Option 2:
Draw->Circle->Center,Radius,
    set radius to 70
    circle center: left endpoint of line
Modify->Move/Copy,
    select the original circle
    base point: left endpoint of line
    target point:  intersection of line auxiliary and circle
    keep original (for copy)
Modify->Delete,
    select the aux circle (70u).