# Pi Day Special: How Much Pi(e) Do You Really Need?

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If any of you made it to this page because you thought this was a food-eating challenge, you certainly might be taken aback but pleasantly surprised at nature of today’s discussion. With the world having celebrated pi day recently, we here at TechQuila hope to highlight the intricate and fascinating particularities of the constant Ï€. Lets start with an interesting fact: A circle has 360Âº and the number 360 takes the 359th position in the decimal.

#### ALL WE KNOW ABOUT PI

Pi, also known as Archimedes’ constant, is an irrational number. That is to say, it is never ending and non-recurring. Ï€ represents the ratio of circumference to diameter of a circle. It is one of the most recognized mathematical constants in the world with endless implementations (staying quite true to the nature of the number). The most digits of Pi memorized is a staggering 70,000. As of today, we know two quadrillion digits after the decimal in Pi. (If you are a Star Trek fan, I hope you remember the episode “Wolf in The Fold”.)

Over the years, our knowledge on the topic has increased. The real question is, how many decimals of Pi do we have to use in real-world problems? Surprisingly, we really dont need that many. NASA scientists keep the space station operational with only 15 digits of pi. For Example, for the Voyager 1, cutting off pi to the 15th decimal only lead to an error of 1.5 inches. To clarify, a 25 billion mile diameter circle will be wrong by 1.5 inches. Of course, the error is negligible.

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TALKING BIG(GER)

Let’s talk on a much larger scale. What if I wanted to calculate the circumference of the entire universe? How many digits of Pi would be sufficient to get an accurate answer? The size of the universe is unknown. However, the size of the visible universe is 46 billion light years. To calculate the circumference accurately, 39 to 40 decimal places of Pi should be sufficient.

In conclusion, if you really want to memorize the value of Pi, stop at 40 decimal places. It won’t really be useful after that. Unless you want to brag. Let me leave you with another interesting fact. 14 March, that is, Pi Day is also Albert Einstein’s birthday.