You can view perimeters for your measurements from the project sheet easily.
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To access the project sheet, click "Sheet" button on measurements section on a residential/commercial/marine project:

On project sheet enable "Show Linear Feet/Metres" checkbox to see the perimeters for each item, room and the project:

Tip: Business owners can enable "Show Perimeters" option from settings > configuration to show perimeters by default on project sheets: