mot can phong dang hinh hop chu nhat co chieu dai 8m,chieu rong 3.8m va chieu cao la 3.9m . Nguoi ta quet voi cac buc tuong xung quanh va tran nha cua can phong do . Hoi dt can quet la bao nhieu m2,biet tongdt cac cuu bang 8.5 m2 ? [chi quet trong phong]