数学题:把一根长30cm，底面半径是8cm的圆木平均锯成4段，每段仍是圆柱体，锯成后的表面积比原来增加多少平方分米(得数保留两位小数）

数学题解答：先弄清一个问题：锯成四段，需要锯几次？

答案是3次。而每锯一次，就会多出2个底面，所以一个多出6个底面。3×2=6（个）

增加的表面积，就是用一个底面积去乘6，算式为：3.14 × 8² × 6 = 1205.76（平方厘米）=12.0576（平方分米）≈12.06（平方分米）

答：锯成后的表面积比原来增加12.06平方分米。

推荐阅读：
5 Thoughts For Investing In Your Freelancing Career In 2017　 How YouTube Can Work in Tandem With Your Blog　 Essena O’Neill Quits Social Media　 Kate Winslet Criticizes Social Media, Parents　 Social Media Quizzes Could Put You At Risk For Hacking　 Freelancing from Anywhere: Tips for Living and Working Abroad　 5 Tools for Busy Bloggers　 #FatGirlsCan Blogger’s Book Released in Paperback　 Cost-Effective Online Management Tools for Bloggers and Small Bu　 Want More Followers? Try Facebook Notes