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)
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! |