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The net work done is the area inside the closed loop in the PV diagram. W = (1.4 * 3)*(106 N/m2)(10-3 m3) = 4.2*103 J, using area = average height * width. or area inside the loop = area of center rectangle + area of to triangle - area of bottom triangle = (1.4*15 + 0.6*15/2 - 0.4*15/2)*(106 N/m2)(10-3 m3) = 22.5*103 J