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如图,某仓储中心有一斜坡AB,其坡度为i=1:2,顶部A处的高AC为4m,B、C在同一水平地面上.
(1)求斜坡AB的水平宽度BC;
(2)矩形DEFG为长方体货柜的侧面图,其中DE=2.5m,EF=2m,将该货柜沿斜坡向上运送,当BF=3.5m时,求点D离地面的高.(5≈2.236,结果精确到0.1m)
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答案(点此获取答案解析)

【解答】解:(1)∵坡度为i=1:2,AC=4m,

∴BC=4×2=8m.

(2)作DS⊥BC,垂足为S,且与AB相交于H.

∵∠DGH=∠BSH,∠DHG=∠BHS,

∴∠GDH=∠SBH,

GHGD

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    Andrew Carnegie was born in 1835 in Scotland. He was from a poor family. When he was twelve, his family moved to the USA. They wanted a better life. There, Andrew started to work right away. He got a job in a factory. He was a good worker, but he didn't like the job. Later, he changed his job. He worked at the Railroad Company where everybody liked him. He did many different jobs. His salary got higher every year.

    In his free time, Andrew loved to read. But in those days, the United States didn't have free public libraries. Luckily, he lived with a rich man with many books, who let young boys use his library for free, so Andrew could read as much as possible. He read throughout his life.

    Andrew learned a lot at the railroad company. He realized that the railroad was very important for big countries. He had a idea to start a business with railroads. He saved all his money and opened a business at the age of thirty years.

    First, his company made bridges for the railroads. Ten years later, it made steel for bridges, machines, and many other things. Soon he was the richest man in the world.

    Andrew liked to make money. But he believed it was very important to help other people. In 1901, he sold his company for $480 million. He started to give away his money to make new libraries and colleges all over the United States. He built 2811 libraries. Andrew also gave a lot of money to people who worked for peace. In 1903, he gave $1.5 million to build a Peace Palace in the Netherlands.

    Andrew Carnegie died in 1919.He was eighty-four years old. During his life, he gave away nearly all of his money. He gave away over $350 million for education and peace. There are colleges, libraries, hospitals, and parks named after Andrew Carnegie.He helped millions of people all over the world to study and learn.