题干

景区大楼AB段上有四处居民小区A,B,C,D,且有AC=CD=DB,为改善居民购物的环境,要在AB路建一家超市,每个小区的居民各执一词,难以确定超市的位置,如果由你出任超市负责人,以便民、获利的角度考虑,你将把超市建在哪儿?

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答案(点此获取答案解析)

【解答】在线段CD上任取一点M,在线段AC上任取一点N,∵AC=CD=BD,∴当超市的位置在M点时,各居民区到超市和=AM+CM+DM+BM=AB+CD=4CD,当超市的位置在N点时,各居民区到超市的路程和=AN+CN+DN+BN=AB+CD+2CN=4CD+2CN,∵4CD<4CD+2CN,∴以便民、获利的角度考虑,将把超市的位置建在线段CD上的任意一点.【分析】此题需先分别计算出当超市的位置在线段CD上和线段CD外,各居民区到超市的路程和即可确定出超市的位置.

同类题2

阅读下面短文,请从A—E五个选项中为每一段选择合适的小标题完成小题。  

    ① ____ It's on the fourth Thursday of November. And it is also a time for tradition and sharing. Even if they live far away, family members gather for a reunion at the house of an older relative. All give thanks together for the good things that they have.

    ② ____ It is on the first Sunday after the full moon which falls on or after March 21st. It is said that on that day Jesus Christ comes back to life. But now for most people, it is a spring holiday, while for children, it means, more than anything else, Easter eggs or chocolate eggs!

    ③ ____ It's also called Double Fifth Festival, is celebrated on the fifth day of the fifth moon of the lunar calendar. It is one of the most important Chinese festivals with a history of more than 2,000years. It was originally designed in memory of ancient poet called Qu Yuan.

    ④ ____ It is a very important Chinese festival. There will be a big family dinner. People who work far away from home will try to come back. At night, people can enjoy the moon while eating moon cakes. They are the special food for this festival.

    ⑤ ____ It falls on the ninth day of the ninth month of the lunar calendar in China. The aim is to promote respect for the elderly. According to centuries-old customs, people climb mountains to admire the view.

A. The Double Ninth Festival    

B. The Mid-autumn Festival C. Easter Day     

D. The Dragon Boat Festival   

E. Thanksgiving Day

同类题4

    Hollywood child star Shirley Temple died on Monday Feb 10th 2014, at home in Woodside, California, from natural causes. "She was surrounded by her family and caregivers," a statement said.
    With her sweet smile and curly blonde hair, she was one of the most popular stars of the 1930s, in hit movies like Bright Eyes and Stand Up and Cheer.
    Her singing, dancing and acting won over fans worldwide. She was given a special Oscar in 1935, when she was just six years old. To this day, she is still the youngest person to receive the award.
    After retiring from films at the age of 21, Temple returned to the spotlight as a politician(政客) and diplomat  (外交官)  .
    Shirley Temple started her film career at three years old. Between 1934 and 1938 she appeared in more than 20 feature films and was the top US movie star at that time.
    As well as being the youngest ever winner of an Oscar (at the age of 6 years and 310 days), Temple was also the youngest person to present one of the statuettes(小雕像). She stood on a chair to give Claudette Colbert the best actress prize for It Happened One Night in 1935.
    At the age of 12 Temple's star burnt out -- her parents stopped her from making movies and sent her to a girls' school. Her final film , A Kiss For Corliss, is available to watch online for free. This is star's final ever moment on the big screen. The actress retired from Hollywood in 1950, but she still appeared occasionally on TV.
    In 2006, she accepted the Life Achievement Award at the 12th Annual Screen Actors Guild Awards.