We can split the shape up into two different shapes. The first shape is the bigger rectangle, with an area of 18 x 30. The second shape will have an area of 6 x (60-18). This is because we have to subtract the length of the large rectangle's side. The two areas are 540 and 252. When we add them together, we get 792. Since this is the area, it will be squared, leaving us with 792 m^2.
