Hi Christina, for this qn I use ratio to solve. Ratio of square p to shaded area is 7:4. Means unshaded area is 7-4 = 3 units. These 3 units = 57cm squared. I divide by 3 units to get 1 unit = 19 cm squared.

Then I times 7 to get the whole shaded area of the square. Once done, I multiply by 3/2, as area of square is 2/3 of rectangle. Once I get the answer of 199.5 cm squared, I proceed to add 57, which is the unshaded part of square p to get the are of the whole figure. Hope this helps !