Here is a handy little subnetwork node: Area.
Just hook it to any polygon and it will return the area of that polygon using the elegant shoelace formula. Works even with very complex shapes. If your shape has multiple contours (like the letter A) you will have to slice it to separate the inner and outer shapes then subtract the inner area from the outer area.
As an added bonus I include another subnetwork node: Find Radius. Regular polygons in NodeBox are defined by their radius, but it would often be preferable to define them by their side length instead. Set the side length and the number of sides in the Find Radius node and it will return the radius required for a NodeBox Polygon node.
Attached is a demo network with shows the perimeters and areas for six different shapes. Enjoy!
John
