Sunday, March 14, 2021

Pi Day 2021

Copyright © Françoise Herrmann

Pi Day is the annual celebration of the mathematical constant designated by the sixteenth letter of the Greek alphabet: π (pi). The constant corresponds to the ratio of a circle’s circumference to its diameter, which means that no matter how small or how big a circle, the ratio of the circumference to the diameter is always equal to the number pi. The number pi also has the particularity of being an irrational number, which means that its decimal form does not end or repeat. For example, modern computers have calculated pi to at least a trillion digits. Thus, pi is usually rounded out to 3.14, which explains the selection of a celebration date on March 14.


Pi enables the computation of such useful measurements as the area of a circle (π x radius2) and the circumference of a circle (pi x diameter), considering that the diameter= 2 x radius. Thus, the algebraic formula of the number pi has countless applications in such domains as building and construction, quantum physics, communications, space flights, air travel, medical practice, plus more.

Specifically, for example, the number pi is routinely used at NASA to track the orbits of satellites and spacecraft, or to learn about moons, planets, stars, and other spherical bodies in space. Still more specifically, for example, NASA carried out a maneuver called pi transfer, using the gravity of Saturn’s largest moon, called Titan, to alter the trajectory of the Cassini space probe, so that the spacecraft could capture different perspectives of Saturn’s rings, during its 13 years in orbit (NASA).

How was the number π discovered? The work of many different mathematicians appears credited for adding precision in the calculation of pi, or for increasing applications of the number pi. However, the discovery of the number pi is traced as far back as the third century BC to the theoretical work of the great mathematician Archimedes of Syracuse [287-212 BC], in a manuscript titled Measurement of a circle. Archimedes approached the calculation of pi with two geometrical figures: a circle and right angle triangle with a base equal to the circumference C, and one side equal to the radius of the circle. He then proceeded by inscribing and circumscribing polygons with an increasing number of sides, within the circle, knowing that the polygon would always be a little smaller than the circumscribing circle, regardless of the number of sides. He estimated pi to be a little less than 31/7th (Encyclopedia Britannica).


The work of the Indian mathematician and astronomer Mādhava of Sangamagrāma  [c. 1340 – c. 1425] of the 15th century, followed by that of William Jones [1675-1749], a Welsh mathematician of the 17th century, further refined the Archimedes estimations and the scope of pi's applications. 

Finally, on an entirely different note, this is a great day for pizza and pie discounts. Hungry? Click here or here for pizza, pie, plus more discounts. As for Martel's Life of Pi (novel) and Ang Lee's feature film Life of Pi,  that is another story altogether. 


 References

Archimedes [287-212 BC] Sphere and cylinder and Measurement of the circle, in T. L. Heath's translation of Archimedes' works. Cambridge, UK: Cambridge University Press (Published in 1897)

Beckman, P. (1970) A history of Pi. New York, NY: St Martin’s Press.

Encyclopedia Britannica – Archemedes  https://www.britannica.com/biography/Archimedes

Lee, Ang (Director) (2012 Life of Pi. Feature film [2h 7m]

Martel, Y. (2001) Life of Pi. Random House Canada

NASA - Cassini spacecraft uses pi transfer to navigate path around Saturn   https://www.nasa.gov/content/cassini-spacecraft-uses-pi-transfer-to-navigate-path-around-saturn/

Pi Day 2021 – Best pizza and pie deals https://www.cnet.com/news/pi-day-2021-best-pizza-and-pie-deals/

The Real Deal – RetailMeNot- 25 Pi Day deals on pizza, pie and more.   https://www.retailmenot.com/blog/pi-day-deals-and-discounts.html


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