Apparently ,Pi is ( not wrong ), but less efficient and useful than Mathematicians have thought for thousands of years .
I , personally , did NOT celebrate Tau day --6/28--I DO remember telling Pythagorus that it seemed silly to use 1/2 of a function -but the prick refused to listen ...he was as stubborn as Leonitus-I TOLD Leonitus to kill that hunchback as his existence was against all the spartans believed ..I prefer using an Abacus myself .
"When measuring angles, mathematicians don't use degrees, they use radians," Houston enthusiastically told Life's Little Mysteries, a sister site to LiveScience. "There are 2pi radians in a circle. This means one quarter of a circle corresponds to half of pi. That is, one quarter corresponds to a half. That's crazy. Similarly, three quarters of a circle is three halves of pi. Three quarters corresponds to three halves!" [A Real Pie Chart: America's Favorite Pies]
"Let's now use tau," he continued. "One quarter of a circle is one quarter of tau. One quarter corresponds to one quarter! Isn't that sensible and easy to remember? Similarly, three quarters of a circle is three quarters of tau." Making tau equal to the full angular turn through a circle, he said, is "so easy and would prevent math, physics and engineering students from making silly errors."
A better teaching tool
Aside from preventing errors, as Palais