Hello @ Charles264
I hope you are doing well, and thank you for reaching out and sharing detailed information.
In Adobe Acrobat, Perimeter measurements are created as measurement annotations, and their numeric value is stored in the Comments panel by design.
Unlike the Distance tool, Perimeter measurements do not always support visible dimension text displayed directly on the page.
See this article for more information: https://adobe.ly/4uFWPz4
Suggestions:
Option 1: View the measurement without opening the full Comments panel
Hover over the Perimeter annotation: The total perimeter value appears in the tooltip
Option 2: Display the Comments list for faster access
Open Comments (right panel or View > Comments). Each Perimeter measurement appears as a single entry with its total value
Option 3: Manually add visible text (workaround)
Create the Perimeter measurement
Use Add Text Comment (or Callout) to manually place the value on the drawing
I hope this helps.
Regards,
Anand Sri.