Your Pi Day festivities may have been canceled this year, but get ready to celebrate Tau Day on June 28th!

The Tau Manifesto proposes that we should all consider — and perhaps teach — the benefits of \(\tau = 6.283185\ldots\) over that in-hindsight-poorly-named \(\pi\). For one thing, by virtue of being the actual circle constant, it simplifies the formula for the circumference of a circle:

\[C = \tau r\]

Then we can compute the area of a circle by summing the areas of an infinitude of infinitesimally thin triangular slices with height \(r\) and combined base lengths \(C\) to find

\[A = \frac{1}{2}Cr = \frac{1}{2}\tau r^2\]

The measure of a full circle is \(\tau\) radians; the measure of one-third of a circle is \(\frac{1}{3}\tau\) radians. And of course \(e^{i\tau} = 1\).

Food for thought.