已知圆锥的底面半径为3cm,母线长为4cm,则该圆锥的侧面展开图的面积为______cm2.
底面半径为3cm,则底面周长=6πcm,侧面面积=12×6π×4=12πcm2.
用所给词的适当形式填空。
1. Hangzhou is a beautiful city in China. A lot of people go ______ (sightsee) there every year.
2. Jim ______ (play) computer games this evening. He doesn't want to go to the movie.
3. Dalian is a beautiful city. I ______ (plan) to go there for vacation again next summer.
4. It's twelve now. The children ______ (have) lunch in the cafe.
5. We ______ (go) to the beach and ______ (go) swimming this weekend.
依据华电集团《反违章管理指导意见》,下列各项中属于指挥性违章的有()。
A.未办理完工作许可手续,做完相应安全措施,就允许工作人员从事相应生产工作
B.没有进行安全技术交底就组织从事生产工作
C.已运行的设备没有运行、检修规程
D.临时爬梯材质不符合要求,挂靠不牢