# Purdue to celebrate Pi Day, role in defending the mathematical constant

March 10, 2015

Edray Goins (Purdue University photo/Tim Brouk) |

WEST LAFAYETTE, Ind. — Purdue University plans to celebrate National Pi Day and an historical refute of an Indiana bill to change the mathematical constant that would have left a sour taste in mathematicians' mouths.

Pi is a number defined as the ratio of a circle's circumference to its diameter and is commonly approximated as 3.14159. However, its decimal representation actually goes on forever and has not yet been found to ever turn into a repeating pattern.

In 1896 Indiana physician and amateur mathematician Edwin Goodwin believed he had a new mathematical recipe for pi and proposed a bill that would have legislated pi, incorrectly, as 3.2. Purdue mathematics professor Clarence Abiathar Waldo pointed out mistakes in Goodwin's calculations, and the Pi Bill was tabled by the Indiana Senate.

This year's Pi Day, celebrated each year on March 14, will be the Pi Day of the century, according to Edray Goins, a Purdue associate professor of mathematics.

"This year brings the most satisfying pi we will likely see in our lifetimes," Goins said. "The year 2015 allows us to take the number beyond 3/14 to 3/14/15. At 9 a.m. and 9 p.m. we can carry the digits even further to 3.14159. That is a big slice of pi."

Purdue's Department of Mathematics and student chapter of the American Mathematical Association will celebrate Pi Day a few days early on Thursday (March 12). A reception, including a selection of pies, will precede a lecture from Francis Su, the Mathematical Association of America president and Benediktsson-Karwa Professor of Mathematics at Harvey Mudd College. The title of Su’s lecture is “Combinatorial Fixed Point Theorems.”

The reception begins at 3:15 p.m. in the Mathematical Sciences Library's lounge, and the lecture begins at 4:30 p.m. in The Richard and Patricia Lawson Computer Science Building, Room 1142.

Su also will meet with the Purdue Math Club at 6 p.m. in Recitation Hall, Room 108. The events are free and open to the public.

Goins has detailed Purdue's slice of pi history on his website at http://www.math.purdue.edu/~egoins/site/Indiana Pi Bill.html and is available to discuss the importance and history of pi.

**Writer:** Elizabeth K. Gardner, 765-494-2081, ekgardner@purdue.edu

**Source:** Edray Goins, 765-494-1936, egoins@math.purdue.edu

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