The answer is: The Area command.
The explanation is shown below:
1. The Area command is a very useful command in AutoCad, and you can use it to calculate the area and the perimeter of a closed region draw with a polyline.
2. To use this command, you only need to type AREA and press the enter button. Then, you must select the points of the closed region and press enter again. Once you do this, the software will show you the perimeter and the area.