It's Pi Day today!

 

It's Pi Day today!



Some interesting stuff on the BBC website. For us mathematical Platonists, pi is as real as a rainbow. I only know Pi approx by heart as 3.1415927, so I'm way below the nerds mentioned below (I do know root 2 and root 3 to the same number of places though!)

Archimedes managed a surprisingly accurate measurement of pi; by a method of differences, he calculated that: "The ratio of the circumference of any circle to its diameter is less than 31/7 but greater than 310/71"

To see how he did it, look here:
http://itech.fgcu.edu/faculty/clindsey/mhf4404/archimedes/archimedes.html

The marvellous Kate Bush, in her album Ariel, has a song called Pi in which she sings her way through over one hundred decimal places of Pi. In fact, she sings 78 decimal places, then loses the next 22 digits before ending with the accurate next 37 digits.

There is some weird and wonderful stuff linking Pi to Stonehenge at:
http://witcombe.sbc.edu/EMIntro.html

I'd be rather suspicious of it; numerologists can do anything; and I've seen links to Stonehenge, Pi and the Great Pyramid (what else!).

Quote:

It's Pi Day, a celebration of the mathematical ratio that man has been trying to unlock for millennia. But why are we driven to find the answers behind it? As we're all taught at school, pi represents the number you get when you divide the distance around a circle (its circumference) by the distance across (the diameter). With just a string and a ruler you can quickly measure that pi must be just over three-and-an-eighth (3.125). With more precise measurements, you may be able to narrow it down to 3.14. SLICE OF PI 3.1415926535 8979323846 2643383279 5028841971 However, if you ask a typical maths nerd, you'll get an earful of pi - 3.14159265 and so on. A surprising number of students have memorised 50 or even 100 digits after the decimal point The rough ratio of pi 3.14 gives us the date for Pi Day. March 14, or 3/14 in American dating style, makes sense for a celebration of this famous constant. Coincidentally, Pi Day is also the birthday of Albert Einstein, who no doubt knew more than a little about pi. Pi Day celebrants, usually children with an enthusiastic teacher and a varying degree of personal interest in the subject, learn about pi, circles, and, if they're lucky, eat baked pies of various sorts. Famous constant Some classes offer prizes for memorising the most digits of pi, or for creating interesting mnemonic devices. Count the letters in each word of this classic poem: Sir, I bear a rhyme excelling In mystic force and magic spelling And while pi is a number, its importance goes far beyond simple geometry. Pi represents a deep universal mystery - how is it that something this basic, this fundamental to maths and science, could turn out to be so incredibly difficult to pin down? In fact, it's literally impossible to know what pi is, because its digits rattle off into infinity. While there are many infinitely long numbers in maths, pi is the only one in which an infinitely simple idea - the circle - unfolds into an infinitely complex value. This paradox drives many people to distraction.

http://news.bbc.co.uk/2/hi/uk_news/magazine/7296224.stm