Just noticed that the perimeter of an element is now listed in AC20's Element Info palette as "Circumference"
A bit of a hoot when it was a rectangular shaped element I was querying
AC versions 3.41 to 25 (UKI Full 5005).
Using AC25 5005 UKI FULL
Mac OSX 10.15.7 (19G2021) Mac Pro-2013 32gbRam AMD FirePro D500 3072 MB graphics