3.768=3.14*2*r 所以r =0.6 S=3.14*r*r=3.14*0.6*0.6=1.13m*m
D=c/π C=3.768/3.14=1.2 S=π(d/2)^2 S=3.14（1.2/2)^2=1.13应该是这样的吧
L=（1.6+1.2）*2-1.2+(2*3.14*1.2/2)/2=6.28米即需要花带6.28米
