Lengths of lines and the areas and perimeters of a polygons are automatically calculated. These measurements are displayed in Object Data by clicking 
on the object.
You can also measure a compilation of areas and lines. As before, click on the object, however, this time hold down the Ctrl key as you click on each. Displayed in the Object Data tab will be:
•Average area
•Minimum area
•Maximum area
•Total area
•Average perimeter
•Minimum perimeter
•Maximum perimeter
•Total perimeter
These values will update as you click on each object.
