Posted by Rallaz on Sep 16, 2014; 10:46am
URL: https://forum.librecad.org/Show-lowest-and-highest-coordinates-of-a-shape-tp5710416p5710419.html

Draw a line to find 90 deg. in arc:
first point use center snap of highest arc
second point use some point outside "bag" using restrict vertical

Draw other line with same method for lowest arc.

Draw vertical dimension using intersection snap of arcs and drawing lines.

Remove temporary lines and ready.

Tip:
Tangent point in arc or circle with horizontal line are in 90 & 270 deg.