问题
解答题
把一个高3分米的圆柱体的底面分成许多相等的扇形，然后把圆柱体切开，拼成一个与它等底等高的近似长方体，它的表面积比圆柱体的表面积增加了36平方分米，求这个圆柱体的体积。
答案
圆柱的底面半径=36÷2÷3=6（分米）
3.14×62×3=339.12（立方米）
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把一个高3分米的圆柱体的底面分成许多相等的扇形，然后把圆柱体切开，拼成一个与它等底等高的近似长方体，它的表面积比圆柱体的表面积增加了36平方分米，求这个圆柱体的体积。
圆柱的底面半径=36÷2÷3=6（分米）
3.14×62×3=339.12（立方米）
假使你是班长，调查了同学们的健康状况，并且列出了调查表。请你根据调查表在活动中发言，倡导同学们要养成健康的习惯，并且给出一些建议。
Hello, everyone! It’s important for us to keep healthy. Many students are 71; it’s bad for our health. We shouldn’t 72 , like hamburgers and French fries. As for eyes, watching too much TV and spending much time playing computer games make our eyes near-sighted. Some students like eating sweet food, so they often have a 73. A few students sometimes have 74 because they never eat breakfast. If we want to keep in good health. I think we should 75. So let’s try to do it! |