Pi Day

Pi Day. Written by Nora Miller.

圆周率日。 诺拉·米勒 著。

Introduction. What's your favorite kind of pie? Apple? Pumpkin? Lemon cream? If you're a mathematician or someone who uses math in your work, it might be something very different. Pie sounds just like pie, but it's the name of a special number that allows people around the world to do many interesting things.

介绍。 你最喜欢哪种派呀？ 苹果派？ 南瓜派？ 柠檬奶油派？ 如果你是数学家，或是工作要用到数学的人，你喜欢的可能完全不一样哦。 圆周率的英文发音和派一模一样，它是一个特殊数字的名字，全世界的人都靠它做很多有趣的事。

What is Pi? The idea of Pi was discovered more than 2 ,000 years ago by a Greek mathematician named Archimedes. He was experimenting with shapes and discovered something strange. He measured the length around a circle called the circumference. Then he measured the distance across the circle from one side to the other through the middle called the diameter. When he divided the circumference by the diameter, he got the same number every time. It didn't matter what size the circle was.

圆周率是什么？ 两千多年前，希腊数学家阿基米德最早发现了圆周率的概念。 他研究图形的时候，发现了一个奇妙的规律。 他测量了绕圆一周的长度，也就是周长。 接着他测量了穿过圆心、连接圆两边的距离，也就是直径。 他用周长除以直径，每次得到的数字都一模一样。 不管圆的大小是多少，结果都不会变。

In 1706, a math teacher in England named William Jones was the first to call this special number pi. It is the name of the Greek letter pi. Now all mathematicians and teachers use that symbol when they talk about Pi.

1706年，英国一位名叫威廉·琼斯的数学老师，第一个把这个特殊数字命名为pi。 pi原本是一个希腊字母的名字。 现在所有数学家和老师讨论圆周率时，都会使用这个符号。

The value of pi is often given as 3 .14, but that is just an approximate value. The numbers to the right of the decimal point actually go on forever. No matter how you calculate it, there are more digits to find. In fact, computers have calculated pi to at least eight quadrillion digits to the right the decimal point. If you tried to write down all those numbers of pi, you'd use enough paper to go around Earth over a million times. There would still be no end in sight.

圆周率的数值通常记为3.14，但这只是一个近似值。 实际上，小数点后的数字无穷无尽。 不管你怎么计算，总能找到更多数位。 事实上，计算机已经算出圆周率小数点后至少八千万亿位了。 如果你想写下圆周率的所有数位，用掉的纸连起来能绕地球一百多万圈。 就算这样，也还是看不到尽头哦。

What can we do with the number pi? It comes from the shape of a circle and has lots of uses. One use is to figure out the area of a circle. Area is the amount of space inside something that is flat. Landscapers use pi to figure out how much area a lawn sprinkler can cover. That amount tells them how many sprinklers they need in order to water a lawn evenly.

圆周率能用来做什么呢？ 它源自圆形，有很多用途。 其中一个用途就是计算圆的面积。 面积就是平面图形所占空间的大小。 园林工人会用圆周率算出一个喷灌喷头能覆盖多大面积的草坪。 知道面积后，他们就能算出需要多少个喷头，才能均匀浇满整片草坪。