I don't know how to get the area of this problem. Please can somebody help me!! Two 9cm X13cm rentables overlap as show to form a 9cmX22cm rectangle.whatis the area of the overlapping rectangular region?

I dont know how to get the area of this problem Please can somebody help me Two 9cm X13cm rentables overlap as show to form a 9cmX22cm rectanglewhatis the area class=