How about a slice of pi?

Thursday is Pi Day, the annual celebration of the mathematical constant π (pi).

Why is it Thursday? Because 3.14 are the first digits of pi, and March 14 is 3/14. (It’s like Star Wars Day, which is May the 4th — “may the force be with you”.)

For those who remember junior high geometry, you’ll recall the formula to calculate the area of a circle, which is π r² (pi times the radius squared). And, of course, for those familiar with the hillbilly joke, there’s the story of the first son to attend college, who comes home and shares what he learned, which is the formula “pi r squared.” The father decides that the cost of college isn’t worth it, because everyone knows “pie are round, cornbread are square.”

Here are some other things to know about pi:

• Pi is an irrational number, which means the exact value can never be calculated. It’s 3.14 followed by an unending string of numbers. Therefore, we can never really find the accurate area or circumference of a circle.

• The infinite, never-ending string of numbers that follow 3.14 can never be determined, but in 2015, a man in India was able to memorize 70,000 decimal places of the value, which took him 10 hours to recite — and he still never got to the end.

• According to Egyptian mythology, it is believed the pyramids of Giza were built on the principles of pi. The vertical height of the pyramids have the same relationship with the perimeter of their base as the relationship between a circle’s radius and its circumference.

• The number pi is very effective when you used in calculations For instance, rounding the number pi to just 9 digits after the decimal and use it to calculate earth’s circumference yield incredibly accurate results. For every 25,000 miles, the number pi will only err to 1/4th of an inch.

• Interestingly, some of the most famous scientists in the world have a connection to Pi Day. Albert Einstein was born on March 14, 1879. Stephen Hawking died on March 15, 2018, at the age of 76.