“桔子香烟”提问：把一块横截面是正方形的长方体木料，削成一个底面最大的圆柱体。底面直径是两分米，高是四分米。求底面削去的面积是多少？这个圆柱体的表面积是多少？

数学题解答：底面削去的面积用正方形面积减去圆的面积就可以了；圆柱体表面积用圆柱的底面积乘高就行了。

底面削去的面积：2×2　-　3.14×（2÷2）×（2÷2）＝0.86（平方分米）

圆柱体表面积：3.14×（2÷2）×（2÷2）×4＝12.56（立方分米）

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