# Rethinking Pi

An interesting idea about Pi has been introduced that can make high school trigonometry less confusing. A circle is defined as “a closed plane curve consisting of all points at a given distance from a point within it called the center.” Since the radius is used to define a circle, then I believe that the radius should be used to define the circle ratio; Pi should have been the ratio of the radius, rather than diameter, to the circumference (this way, the value of Pi would be doubled). A full circle, 360 degrees, would be Pi radians if the value of Pi were approximately 6.

28 instead of approximately 3.14, so it makes more sense to me that the ratio associated with circles should be approximately 6.28. Since people have been using Pi for a long time, replacing Pi would be too difficult. Instead of redefining Pi, mathematicians have proposed using the Greek letter Tau to represent two times Pi. This would make the concepts that we high school students learn in math class seem more natural and less confusing.

Pi divided by six is one twelfth of a circle, while Tau divided by twelve is one twelfth of a circle. By using Tau, there is less work needed to memorize the unit circle when taking trigonometry classes. There are other examples where using Tau instead of Pi is more useful. I was introduced to this idea by reading “The Tau Manifesto” by Michael Hartl. Although other works have been done on this subject, I wrote this to introduce more teenagers to the idea.

I encourage those who like this idea to read more about Tau, start using Tau more, and celebrate “Tau day” on June 28th.