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如图所示,要在离地面5m处引拉线固定电线杆,使拉线和地面成60°角,若考虑既要符...
如图所示,要在离地面5m处引拉线固定电线杆,使拉线和地面成60°角,若考虑既要符合设计要求,又要节省材料,则在库存的l
1=5.2m、l
2=6.2m、l
3=7.8m、l
4=10m四种备用拉线材料中,拉线AC最好选用( )
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131103101408135710790/SYS201311031014081357107016_ST/images0.png)
A.l
1B.l
2C.l
3D.l
4
考点分析:
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