The Area tool is used to measure the area of an irregular polygon. The polygon boundary is defined by a series of points entered by the pointer device. The boundary can be convex or concave, but it can't intersect itself. If the boundary is self-intersecting the results are undefined.
Once the points have been entered, circular handles are shown at each vertex of the boundary. These handles can be dragged as needed to adjust the boundary.
The options described below can be found in the bottom app bar or in the control panel.