Polygon

A closed shape with as many corners as you like. Click each corner; double-click or press Enter to close it.

Why you would use it

To ring an area that isn’t a rectangle. A box round an L-shaped room includes half the corridor and invites the wrong answer.

For example

What to do

1. Click each corner.
2. Double-click or press Enter to close it.
3. Backspace removes the last point.

Going further

Nothing here is measured. Polygon area, under Measure, is the tool that reports a quantity.

If you already use another program

In a CAD program: A closed polyline.

In a PDF markup program: A polygon markup.