Google Logo for Pi Day

Google updates its logo every now and then. But this one catches my attention: π day. March 14.



In the math book I used in elementary school, it says π is approximately 3.14 or 22/7. It also says 3.1416 is a better value. The curious me punches out 22/7 on the calculator and of course it is 3.142857. Waita minute it is not 3.1416. Then I saw the word "estimate" Ok, I am cool with that.

No elementary school text ever explains where 3.1416 comes from. I thought: ah, there must be some very precise ruler that measures the circumference and divide by the diameter to get that 3.1416. Later, I found out extreme nerdy people challenge themselves by memorizing the never ending digits of π

How do you get that many digits?

I didn't know how to get digits of π until much later...

Here is one way to find the digits of π. Draw a circle, let radius =1. What's the area? Yes, it is π r², and it is just... π. If you can find the area of this circle you got π. How do you start? Look, you can draw polygons inside and outside and the area of the circle must be in between! This is Archimedes's brilliant idea!

Oh, there are so many such formula and gosh some are so "elegant"

Whoa, look at the Leibnitz Formula. Whoa, look at the Wallis Formula.

π is so fascinating. So there is Pi Day. Waita minute what's the purpose of π day? To eat different types of π.

Joke:
A: Can you tell me a formula for pie?
B: pi r squared?
A: No, pies are round, CAKES are square.

Happy Pi Day.