Miscellaneous: I actually Used Pi to Solve a Real-life Problem

In high school, I got it into my head that it would be impressive to memorize the value of π to 100 digits. I don't remember why. It was just one of those things.

I started out with enthusiasm but quickly abandoned the project because of something my girlfriend's mother said as I was attempting to rattle off what I had learned--she questioned the need to memorize 100 digits if my intent was just to impress people. She reasoned that most people probably know the value of π to four or five digits at most. Therefore, she said, it would be more efficient to memorize the first 10 digits or so and then make up the rest because almost no one listening would ever know the difference.

At this remove, I've retained the value of π in my head to nine digits--3.141592635. That seems like plenty to impress and for practical use, and yesterday I used π to solve a real-life problem. I was drilling drainage holes in ceramic pots. I was trying to decide whether it was more efficient to drill three 3/4-inch holes in the bottom of each pot or to drill two one-inch holes. To compare the area opened up by each of the two options I had to know the value of π. Three 3/4-inch holes gives 7.0 square inches of drainage (0.75 x 3π), while two one-inch holes gives 6.3 square inches (2π)--close enough given how hard it is and how long it takes to drill holes in a thick ceramic material. Nine digits was more than enough to do the calculation. Thanks Mrs. Knoll.