我试过用游标卡尺来测量,readability0.01mm. L1=63.50mm L2=63.00mm W1=119.28mm W2=119.58mm suppose to be a ideal rectangle, then Amin=7514.64mm2 Amax=7593.33mm2 Difference : 78.69mm2 I also ever tried the DVM with image pro. plus, which give the A=7628.109mm2 bigger than Amin and Amax by vernier caliper.