As shown in the figure, the quadrilateral ABCD and the quadrilateral defg are both square. The area of the triangle AFH is known to be 6 square centimeters, so the area of the triangle CDH can be calculated

As shown in the figure, the quadrilateral ABCD and the quadrilateral defg are both square. The area of the triangle AFH is known to be 6 square centimeters, so the area of the triangle CDH can be calculated

If FD is connected, the triangle FDC and the triangle AFD have the same base and height, then their areas are equal. If FHD is subtracted from the common part of the triangle, then the remaining areas are still equal, that is, the areas of the triangle AFH and the triangle CDH are equal, so the area of the triangle CDH is also equal to 6 square centimeters