To find the area of the shaded area you have to find the find the area of the two shapes shown in the problem which is the white square and blue rectangle. The formula is easy because they are both squares. So:
A= 12 * 18 is 216 and A= 8 * 8 is 64
Then to get the area of just the blue rectangle you have find the difference between both areas which is the answer: 152cm^2
