题干

我国南水北调中线工程的起点是丹江水库,按照工程计划,需对原水库大坝进行混凝土加高,使坝高由原来的162米增加到173米,以抬高蓄水位.如图是某一段坝体加高工程的截面示意图,其中原坝体的高为B,背水坡坡角∠BAE=68°,新坝体的高为DE,背水坡坡角∠DCE=60°.求工程完工后背水坡坡底端水平方向增加的宽度AC.(结果精确到1米.参考数据:sin68°≈0.93,cos68°≈0.37,

tan68°≈2.50, 3 ≈1.73).

上一题 下一题 0.0难度 选择题 更新时间:2016-07-01 05:31:03

答案(点此获取答案解析)

解:在RT△BAE中,∠BAE=68°,BE=162m.

∴AE=64.80,

在RT△DCE中,∠DCE=60°,DE=173.

∴CE= DEtan60

同类题5

完形填空

    The following is a beautiful speech by Sundar Pichai, a senior executive at a big IT company. At a 1 a cockroach (蟑螂) suddenly flew from somewhere and sat on a lady. She started2 out of fear. With a panic-stricken face and trembling voice, she started jumping, with both her hands 3 trying to get rid of the cockroach. Her 4was contagious (传染的), as everyone in her group also got5.The lady finally managed to push the cockroach away but it6on another lady in the group.

    Now, it was the7of the other lady in the group to 8 the drama. The waiter rushed forward to their9.In the relay of throwing, the cockroach next fell upon the waiter. The waiter stood10calmed himself and observed the behavior of the cockroach on his shirt. When he was11 enough, he grabbed it with his fingers and 12 it out of the restaurant.

    Sipping my coffee and watching the amusement, I picked up a few thoughts and started wondering13 the cockroach was responsible for their behavior. If so, then why was the waiter not 14.He handled it near to perfection, without any15It was not the cockroach, but the 16of the ladies to handle the disturbances caused by the cockroach that disturb the ladies. I17that, it is not the shouting of my father or my boss or my wife that disturbs me, but my inability to handle the disturbances 18by their shouting that disturbs me. It's not the traffic jam on the road that disturbs me19 my inability to handle the disturbances caused by the traffic jam that disturbs me20 than the problem, it's my reaction to the problem that creates chaos in my life.