Element Information will give you the length of a polyline.
Unfortunately you can't schedule a polyline - I don't think you can label the length either.
But you can schedule a fill - this will give you area and perimeter.
One of the forum moderators.
Versions 6.5 to 25
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Dell Precision 3510 - i7 6820HQ @ 2.70GHz, 16GB RAM, AMD FirePro W5130M, Windows 10