How Long Is a Year…In Terms of p?
Jason Marshall, PhD
Here’s a handy number that astronomers (myself included) use all the time when making calculations that I think everybody should have in their number-crunching bag-o-tricks:
1 year is about π • 107 seconds.
In other words, if you multiply the number π ≈ 3.14 by the number 107 = 10 million, the result is pretty close to the total number of seconds you age each and every trip around the Sun.
Of course, the length of a year doesn’t actually have anything to do with the ratio of the circumference of a circle to its diameter (which is where π comes from). This is all just a happy accident.
To hammer this home, the precise number of seconds in a 365 day year is: (60 sec/min) • (60 min/hr) • (24 hr/day) • (365 day/year) = 31,536,000—which isn’t exactly π • 107. But it’s only off by 0.4%, so it’s a very good approximation!
The great thing about memory tricks like this is that even though you might not need to use them all the time, they’re easy to remember…so they’re right there for you if (or rather when) you need them!
Pie image courtesy of Shutterstock
About the Author
Jason Marshall is the author of The Math Dude’s Quick and Dirty Guide to Algebra. He provides clear explanations of math terms and principles, and his simple tricks for solving basic algebra problems will have even the most math-phobic person looking forward to working out whatever math problem comes their way.