题干

如图,点A、B、C表示某旅游景区三个缆车站的位置,线段AB、BC表示连接缆车站的钢缆,已知A、B、C三点在同一铅直平面内,它们的海拔高度AA′,BB′,CC′分别为110米、310米、710米,钢缆AB的坡度i1=1:2,钢缆BC的坡度i2=1:1,景区因改造缆车线路,需要从A到C直线架设一条钢缆,那么钢缆AC的长度是多少米?(注:坡度i是指坡面的铅直高度与水平宽度的比)

上一题 下一题 0.0难度 选择题 更新时间:2019-12-16 09:40:26

答案(点此获取答案解析)

解:过点A作AE⊥CC′于点E,交BB′于点F,过点B作BD⊥CC′于点D,

同类题2

阅读理解

    New York Time—A gunman killed eight people at a mall in Omaha this afternoon and then killed himself, setting off panic among holiday shoppers, the police said.

    "The person who we believe to be the shooter has died from self-inflicted gunshot wounds," Sergeant Teresa Negron of the Omaha Police Department said at televised news." We have been able to clear the mall," she said." We don't believe we have any other shooters." The police said that at least five other people had been injured in the shootings.

    She did not give the shooter's identity." We are still conducting the investigation," Sergeant Negron said, adding that the city's mayor, who was out of town, was on his way back to Omaha.

    She said the police received a 911 call from someone inside the Westroads Mall on the west side of Omaha, and shots could be heard in the background. The first police officers arrived at the mall six minutes after the first call, she said but by then the shootings were over.

    It is reported that the gunman left a suicide note that was found at his home by relatives. A law enforcement official who spoke on condition of anonymity(匿名)said the note indicated that the gunman wanted to "go out in style."

    The shootings broke the usually ordinary routine of holiday shopping. The gunman was said by some witnesses to have fired about 20 shots into a crowd. Some customers and workers ran screaming from the mall, while others dived into dressing rooms to hide from the shooter.

    Shoppers and store workers were trapped inside the mall, which has roughly 135 stores. Others streamed out of mall exits with their hands raised. President Bush was in Omaha this morning to deliver a speech, but he had left the city by the time the shootings took place.

根据短文内容,请将单词填写在题号对应的横线上。