兰州拉面的制作步骤是：将一个面团先搓成圆柱形面棍，长1.5米，然后对折拉长到1.5米，再对折拉长到1.5米…照这样继续下

Lanzhou beef noodles was founded in Guangxu years, the Department of the elderly MA Bao-Hui son first, in the near century long years, to a bowl and renowned Jincheng to rotten meat, flour quality and fine reputation of Chinese and foreign, to enter the country. During crystallization of MA Bao-son and the subsequent numerous franchise beef noodle soup cooks wisdom and painstaking efforts. Today, because of delicious beef noodle soup delicious, affordable, not only abound in Lanzhou, and have been all over the Northwest provinces, there has been many places Lanzhou beef noodle shop. However, one out of Lanzhou beef noodles on , it is necessary to get the real authentic or in Lanzhou beef noodles. Visitors to the Maryland deserve a taste.
Lanzhou beef noodles about "one-ching, II white, three red, four green, five yellow", or beef-ching gas liquor color incense; radish pure white tablets; red chili oil floating; coriander, fresh green ; noodles are silky yellow permeability. Noodles according to thickness can be divided into the big wide, wide, thin, two small, capillary, leek leaves, bridge types, such as wheat spinulosa. Noodles by hand drawing the scene into a bowl of less than two minutes to do a good job, and then doused with good tune beef soup, white films, transferred on the red chili oil, green , coriander, food is the wow.

解题思路：设面条原来的半径为r，最后拉出的面棍粗细仅有原来面棍的[1/64]，则此时面条的直径是[r/64]，由于虽然面条的长度发生了变化，但是体积没有发生变化，设最后的长度为x，根据圆柱的体积公式可得方程：1.5××π×r²=πx(

r

64

)2．

设面条原来的半径为r，最后的长度为x，可得方程：
1.5×π×r²=πx(
r
64)2
1.5×r²=
r2
4096x，
[x/4096]=1.5，
x=6144．
答：最后面条师傅拉出的这些面条的总长度有 6144米．
故答案为：6144．

点评：
本题考点： 分数和百分数应用题（多重条件）．

考点点评： 明确这一过程中，拉面的体积没有变，并由此列出方程进行分析是完成本题的关键．

7.5*64
就是这样