first of all you are gonna make that into two rectangle by slicing the top off if that makes sense so you now have a large rectangle (11×12) and a small one (3×8) now you use the area formula for rectangles base×height so the small one becomes (3×8)=24 and the large one is (11×12)=132. now to make them into one shape for the total area you add those two values 132+24=156 so your total area is 156m²
