1. Problem statement. We are given a rectangular ground floor of width $15$ m and height $20$ m, divided into three stacked rectangles: a top garage of dimensions $15\times4$, a middle band containing a living room of dimensions $12\times12$ and a hall of dimensions $3\times12$, and a bottom kitchen of dimensions $15\times4$. 2. Verify the vertical partition. Check that the heights add to the total height. Compute $4+12+4$. Display: $$4+12+4=20$$ This confirms the vertical partition matches the total height. 3. Compute individual areas. Compute the area of the garage using $A_{garage}=width\times height$. Display: $$A_{garage}=15\times4=60$$ Compute the area of the kitchen using the same formula. Display: $$A_{kitchen}=15\times4=60$$ Compute the area of the living room using the square formula. Display: $$A_{living}=12\times12=144$$ Compute the area of the hall using $width\times height$. Display: $$A_{hall}=3\times12=36$$ 4. Check the total area. Compute the total floor area directly from the outer rectangle. Display: $$A_{total}=15\times20=300$$ Compute the sum of the parts and verify it equals the total. Display: $$60+144+60+36=300$$ This confirms the partition of areas is consistent with the whole. 5. Final answers. Garage area is $60$ square metres. Kitchen area is $60$ square metres. Living room area is $144$ square metres. Hall area is $36$ square metres. Total floor area is $300$ square metres.