Determining the Difference in Area between Inner and Outer Polygons?

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03-14-2011 07:20 AM
ClaytonAnderson
New Contributor
Ok. I just started having to use ArcGIS again after a year and a half of absence, so I'm pretty rusty and can't remember how to do this...

I need to be able to determine the area of a polygon around another polygon excluding the inner polygons area. If that makes sense.

ATM when I place a polygon on the map and another "inside" it, it is more like placing it on top and still calculating the original area, where as I need it to exclude the new polygon's area automatically

attached is a crude representation of what I'm after. I need the final A1-A2=A3

Any help would be appreciated, I know there is a simple solution but I can't seem to track it down
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DonovanCameron
Occasional Contributor II
Using Graphics: Reverse-clipping

Editing Session: Polygons subtraction

Once the clip is completed, the area field will need to be re-calculated in shapefiles (not for feature classes - stored in a gdb). This is done with the Calculate Geometry feature in the attribute table.
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