设塔高AE=x,作CF⊥AB于点F,
则四边形BDCF是矩形,
∴CD=BF=30m,CF=BD,
∵在Rt△ADB中,∠ADB=45°,
∴AB=BD=x+62
—I think teenagers should be allowed to make their own decisions when they have problems at school.
—_______. They're not calm enough, after all.
如图所示,上下开口、内壁光滑的铜管P和塑料管Q竖直放置,小磁块先后在两管中从相同高度处由静止释放,并落至底部,则小磁块( )
如图表示广州市家用燃料使用的发展历程(括号内表示主要成分),下列说法错误的是( )