If the big square is 5 and the small square is 3, then the bottom is 3+5=8, and the blank triangle in the lower right corner is (8*3) divided by 2 equals 12.

The one in the upper left corner is 5×5÷2, which is equal to 12.5.

The sum of the areas of the big square and the small square is 5× 5+3× 3 = 34, and the area of the shaded part is 34- 12.5- 12=9.5.