Pi Day — or Tau Day???

This is a few days late, but…

We held our annual observation of Pi Day on Monday in two of my classes and on Tuesday in the other two (since they didn’t meet on Monday). But one of my students pointed me to a couple of posts claiming that pi is wrong — not wrong in the sense that the ratio of the circumference of a circle to its diameter isn’t actually π, nor wrong in the sense that π doesn’t have the value we think it does (of course it’s the right ratio and does have that value) but wrong in the sense that it would be much more useful and pedagogically better to use the ratio of the circumference to the radius. This ratio, called tau (τ) is explored by Vi Hart in her usual inimitable manner. Do watch her video!



Categories: Math, Teaching & Learning