3.7×1.6+3.7×1.2×2+1.6×1.2×2=5.92+8.88+3.84=14.8+3.84=18.64平
按展开面积算 要做的几个面加起来就是总平方数
3.7×1.2+3.7×1.6×2+1.2×1.6×2=4.44+16.28+20.12=40.84（m²）
