http://thehousenews.com/nature/% ... 6%95%B8%E5%AD%97Pi/
美國人口 http://www.census.gov/main/www/popclock.html http://www.census.gov/newsroom/r ... ion/cb12-tps52.html
Shortly after 2:29 p.m. EDT today, the U.S. population clock will reach a milestone that is very meaningful to mathematical statisticians: it will show there are 314,159,265 residents, or pi (3.14159265) times 100 million. Pi is a mathematical constant that is the ratio of a circle's circumference to its diameter. “This is a once in many generations event...so go out and celebrate this American pi,” said Census Bureau Chief Demographer Howard Hogan. Internet address: .2 : GS(14)@2012-08-18 15:49:14