Open your mouth wide like a circle, now say "Tau", and no more Pi for you!
I'm not a good mathematician. But I did know how to work out the length of the circumference and the area of a circle, if given the diameter. You simply used an incredibly complex number represented by the Greek letter π which is the ratio of the circumference to the diameter of any circle.
I was very interested to read an article today that suggests, nay proves, that π would be better thrown out and we should really work with a constant that is based, not on the diameter, but the radius. The Tau Manifesto by Michael Hartl, proposes the use of a new constant that is twice π, called Tau () instead of Pi (π).
ie. τ = 2π
A seemingly simple change. Yet, having introduced circle functions to 8 - 12 year-olds, I can tell you, Tau would be so much easier for young people (and everyone!) to understand and use than Pi.
It seems astonishing that something that we have used for so many centuries might be improvable.
You might like to read the Manifesto and make up your own mind.