## Celebrate Pi Day -- March 14

What is Pi? Pi (`π`

) is approximately 3.14159, the mysterious mathematical constant which represents the ratio of any circle's circumference to its diameter. It is "approximately" because Pi itself is what is termed an "irrational number". That means it never repeats or ends. It keeps going and going forever.

Pi Day is celebrated on March 14 (3/14) each year in honour of Pi. It was first founded in 1988 at the Exploratorium in San Francisco by physicist Larry Shaw, and in 2009 the US House of Representatives designated March 13 as "National Pi Day". On Pi Day, math nerds everywhere celebrate the beauty of Pi's infinite progression of numbers. Schools around the nation take the occasion of the holiday to explore the significance of this number. It is currently treated as a day of mathematics, fun, and an excuse to have more pie.

### How many digits of Pi do you know?

__To 550+ digits__

28620899862803482534211706798214808651328230664709384460955058223172535940

81284811174502841027019385211055596446229489549303819644288109756659334461

28475648233786783165271201909145648566923460348610454326648213393607260249

14127372458700660631558817488152092096282925409171536436789259036001133053

05488204665213841469519415116094330572703657595919530921861173819326117931

05118548074462379962749567351885752724891227938183011949129833673362440656

643086021394946395224737190702179860

__How to estimate Pi by throwing frozen hot dogs__

This is a strangely satisfying activity, by the way.

- Get the hot dogs out of the freezer.
**Tip**: Actually, this will work with almost any "straight" food item of a suitable size (about 30cm) and stiffness. Celery, churros, and uncooked spaghetti noodles are great options if you don't have frozen hot dogs. If the food items are not of uniform length, cut them to size. - Select a spot in the kitchen from which to throw your hot dogs.
- Clear the area of any potential obstacles.
- Measure the length of your hot dog and write it down.
- Use masking tape to mark lines on the floor which are perpendicular to the throwing direction. Space the tape strips far enough apart to match the length of your hot dog.
- Set up a chart on paper with columns for "Toss" (to mark how many times a hot dog is thrown) and "Cross" (to mark how many times a hot dog lands across a tape line).
- Throw your hot dogs one at a time, recording your data as you go along. If you run out of hot dogs, collect them back up and keep throwing. By 200 throws, you should see a pattern.
- Once finished, divide the number of crosses by two, then divide the number of tosses by the result. Your end result should be an approximation of Pi.

### Pssst! Your math geek is showing.

The numeric character reference in HTML for Pi is `Π`

(displays as "`π`

").

__Say it in maths__

Area of a circle = `π`

r^{2}

Circumference of a circle = 2`π`

r
(where "r" = radius)

__Five foods to eat while celebrating Pi Day__

Round foods are of course best for this purpose, taking the time to calculate both the area and circumference of the circular food in question.

- Pie (any type of pie will do)
- Pizza pies
- Cookies and cakes with a "pi" symbol on the top in icing
- Coffee, pie, and doughnuts, which is a mnemonic for the equation Circumference equals (Pi multiplied by Diameter) => C =
`π`

d (Coffee, Pie, Donuts) - Any other round food will work in a pinch. M&Ms, Skittles, round cereals ...