Work out the area of each rectangle separately and then add them up altogether.
Chat with our AI personalities
A polygon with no congruent sides is not going to have any convenient formula by which the area can be calculated, however, you can always break it up into a series of triangles and rectangles, and then calculate the area of those, and add up the results.
The question needs to be more precise. As stated, the shape can be any polygon with an even number of sides.
You could consider the cross as two intersecting rectangles. Calculate the area of both rectangles and the area of the intersection (overlap). Then area of cross = sum of the areas of the rectangles minus the area of the overlap.
Finding the perimeter of a polygon is finding how far it is in total along all the edges of the polygon; whereas finding the area of a polygon is finding how much space the polygon covers. The perimeter of a polygon forms the boundary around the area of the polygon.
When rectangles are inscribed, they lie entirely inside the area you're calculating. They never cross over the curve that bounds the area. Circumscribed rectangles cross over the curve and lie partially outside of the area. Circumscribed rectangles always yield a larger area than inscribed rectangles.