Choose Inspect tab→2D Measure group→Measure Area 
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Click inside a closed boundary to measure its area.
To measure the total area in more than one boundary, press the Shift key and click inside the next boundary.
Tip:
If you are measuring multiple areas and want to clear the total measurement, click anywhere without pressing the Shift key.
In Draft, when measuring within or to a drawing view, you can choose to display the value using the model distance or a user-defined distance by selecting a scale option on the Measure Area command bar.