This is a play on words on the well known area of a circle formula; (pi)r^2 pi= 3.14 and r stands for your radius. BTW Pie are round.
http://wiki.answers.com/Q/What_is_pie_are_square

The formula for the area of a circle is Area = πr^2, where r is the radius of the circle and π = 3.14. If you have a circle with radius of r = 3, then the area of the circle
http://answers.yahoo.com/question/index?qid=200904...

The equation would be 4/3(3.14r2) with the 2 standing for the squared
http://www.chacha.com/question/whatistheequatio...

The wikipedia page probably contains everything you need to know: http://en.wikipedia.org/w. iki/Coe. In the context of linear models, which is usually where. comes up, here are two
http://www.quora.com/Statisticsacademicdisciplin...
