???????

???????????

1220??*2440??*20?? ???????1?22?2?44 ??20??????2.0.

?20??????????2.0??????????????????????

???????????

1.22*2.44*0.02=0.05936????

??????????

????? 900*4.2m*18mm??????????????????????????????????????

??????????900*4200*18=68040000????

?????????:90*420*1.8=68040????

????????:0.9*4.2*0.018=0.06804???

??????????1???1???1???????????????????????

???????????0.11???