问题
填空题
一个梯形的面积是36cm2它的上底是3cm，高是8cm，它的下底是______．
答案
设梯形的下底为x厘米，
（3+x）×8÷2=36，
（3+x）×8=36×2，
（3+x）×8=72，
3+x=72÷8，
3+x=9，
x=9-3，
x=6，
答：它的下底是6厘米．
故答案为：6厘米．
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一个梯形的面积是36cm2它的上底是3cm，高是8cm，它的下底是______．
设梯形的下底为x厘米，
（3+x）×8÷2=36，
（3+x）×8=36×2，
（3+x）×8=72，
3+x=72÷8，
3+x=9，
x=9-3，
x=6，
答：它的下底是6厘米．
故答案为：6厘米．
| 阅读下面的短文，从文后方框中选择恰当的句子填入文中空白处。 | |
| When you read this sentence, the population of the earth has grown by 10 people. 1.________ Most of these new people are born in developing countries. 2.________ In the developed countries of Europe and North America, the population is growing very slowly. This is because women in these countries have, on average (平均), only one or two children. 3.________ In the developing countries, more than one billion people already live below the poverty line (贫困线). 4.________ Children get little or no time at school and suffer from many kinds of diseases. The UN has said that the world's population will reach 12.5 billion people by the year 2100. If the number makes your head spinning (眩晕), you're not alone. Many experts are worrying that so fast population growth could have very bad results. 5.________
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