题干

如图所示,污水处理公司为某楼房建一座周长为30米的三级污水处理池,平面图为矩形ABCD,AB=x米,中间两条隔墙分别为EF、GH,池墙的厚度不考虑.

(1)用含的代数式表示外围墙AD的长度;
(2)如果设计时要求矩形水池ABCD恰好被隔墙分成三个全等的矩形,且它们均与矩形ABCD相似,求此时AB的长;
(3)如果设计时要求矩形水池ABCD恰好被隔墙分成三个全等的正方形.已知池的外围墙建造单价为每米400元,中间两条隔墙建造单价每米300元,池底建造的单价为每平方米100元.试计算此项工程的总造价.(结果精确到1元)

上一题 下一题 0.0难度 选择题 更新时间:2018-09-11 12:32:12

答案(点此获取答案解析)

解:(1)∵矩形周长为30米,AB=x米
∴AD=30
2
-x=(15-x)米
(2)由题意可知矩形的周长为30米,AB=x,所以<

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Dear Boarding Students,

      At this time of school year, we can feel some students begin to experience excitement as the summer vacation comes. But some others still don't want to start packing. I once again ask for your attention as we will have summer camps for the new students. There is much work to be done in packing and cleaning-up,especially during exam week.

              ▲      Each student will get a task list and each task has a deadline(期限). The dorm(寝室)teachers will work with each student each night to make sure you are getting the tasks done on time. It would be helpful if your parents encourage you to do a little packing and cleaning from now on. It means you can take the posters off the wall,pack up winter clothes,return all borrowed books to the library,etc. Spending twenty minutes a day on your tasks will make the last week of the term very easy,and you can spend more time on the important preparation for exams. If you plan to travel home,I'd like to remind you to take some of your belongings with you.

      The coming weekend is a "closed weekend". During that time no one is allowed to leave school. After packing we need to prepare the dorms for moving out,and store(储藏)students' large belongings.

      The last exam is on Thursday and all students leave after their exam. The dorm will remain open until 5 p. m. on Friday for those students that could not get a ride or flight. Please let us know if you need transportation to the airport.

      Thank you again for all your attention during the last,busy month of school. As always,you,welcome to call or email me with any questions.

    Peter Margio

    Director of Campus Life

      453-757-2630

    pmargio@ baylinschool. com