First I look at a figure with 3 points. The points are draggable.
You should be able to see the coordinates of the points, the
length of the sides, the measure of the angles, and the area of the
triangle.
Next I try one with 4 points. The points are draggable. You should be able to see the coordinates of
the points, the length of the sides, the measure of the angles, and the
area of the quadrilateral.