Because the proportional relationship between the upper and lower bottoms of the trapezoid is not considered, it is treated as a rectangle. The answer area = 675m2, converted into mu =1.0125mu.
Meaning of supplementary question: If vegetable field is understood as a quadrilateral structure, then the total length of the fence is determined as three sides of the quadrilateral, and the fence part is one side. In fact, there are two answers to this question: because the ratio of the upper and lower bottoms of the trapezoid is not set, it can actually be understood as a rectangle or parallelogram through the "excavation and filling method"; The fence is used as the long side of the rectangle. The answer should be that the fence is 45 meters long, that is, "45"+15+45+15; The length (width) used as the short side should be 15m, that is, "15"+30+15+30, so the area will have two results.