\(\begin{array}{l}{S_{ABCD}} = AD.AB\\ = (20 + 40).(40 + 10 + 35) \\= 5100({m^2})\\{S_I} = \dfrac{1}{2}.40.20 = 400({m^2})\\{S_{II}} = \dfrac{1}{2}.10.20 = 100({m^2})\\{S_{III}} = \dfrac{1}{2}.(20 + 35).35 = 962,5({m^2})\\{S_{IV}} = \dfrac{1}{2}.15.50 = 375({m^2})\\{S_V} = \dfrac{1}{2}.(15 + 40).15 = 412,5({m^2})\end{array}\)
Diện tích phần gạch sọc :
\(S = 5100 – ( 400 + 100 + 962,5 + 375 \) \(+ 412,5) = 2850\,(m^2)\)
