Pi Day: How Pi Was Almost Changed to 3.2

Pi as we know it could have changed forever, thanks to a late 19th-century bill introduced in Indiana

March 14 is Pi Day, an annual celebration of the world’s most famous number, pi. Founded in 1988 by physicist Larry Shaw, March 14 was selected because the numerical date (3.14) represents the first three digits of the number. However, if a certain late 19th-century physician and amateur mathematician, Edward J. Goodwin, had had his way, pi would have been rounded up to 3.2, which means we’d be celebrating Pi Day, if at all, on March 2. How did that come about? Read on, young pi-diwan—and make sure you read some pi jokes and cash in on Pi Day deals to celebrate this mystery number.

Why is there a need for pi?

No matter what size circle you can imagine, its circumference divided by its diameter is always the same: 3.14 (followed by an infinite number of decimal expansion that, as of today, has been calculated to more than 100 trillion decimal places). That makes 3.14 not only an irrational number (because its decimal expansions are infinite) but also a “constant,” at least with regard to calculating the measurements of a circle. This constant was discovered in the third century B.C. by the ancient Greek mathematician Archimedes and is essential not only to high school geometry but also to engineering (which could explain why pi is the unofficial “patron” number of the Massachusetts Institute of Technology). In 1706, it became known as the Greek letter π or pi, which stood for the Greek word for “perimeter,” which is another word for “circumference.”

Fun fact: Although pi was identified by Archimedes, it had already been in use for thousands of years.

The obsession with “squaring the circle”

To a layman, pi as the constant that makes a circle have the qualities of a circle might seem like a near-perfect concept. To mathematicians that came after Archimedes, however, it was maddening. This was because with the irrational number, pi, as its constant, a circle could never be turned into a square, at least not without changing its area, losing or gaining unintended geometric “area” (i.e., the space occupied by a flat shape).

Interesting fact: In 1882, “squaring the circle” was declared “impossible.” That proved undaunting, however, to Dr. Goodwin, who believed it wasn’t “impossible” so much as “obstructed” by inherently incorrect, albeit long-accepted formula for calculating the area of a circle. Eventually, Goodwin realized that if you simply rounded 3.14 up to 3.2, you could actually square a circle.

The only problem: Goodwin was wrong with this math trick. Ask any sixth-grader, and they’ll tell you if you want to turn 3.14 into a two-digit number, it doesn’t round-up but rather becomes 3.1. Oops. Nevertheless, Goodwin managed to convince Indiana State Representative Taylor Record to introduce a bill in the state’s General Assembly of 1897 to make Goodwin’s method of squaring a circle a matter of state law—despite that legislation is not and never has been the academically accepted way to establish the truth of a mathematic discovery.

Why the idea of changing pi gained steam

There’s a logical fallacy called the “appeal to ignorance” that has us assuming that what we don’t understand must be either (a) wrong or (b) over our heads. When Indiana state lawmakers found the resulting bill confusing, they went with (b) and proceeded to pass the bill through various committees on February 6, 1897.

Purdue University saves pi as we know it

Before the bill got to the state Senate, however, a Purdue University math professor, Clarence Waldo, just happened to be hanging around the capitol (he was seeking funding for the Indiana Academy of Sciences), where one of the legislators happened to show him the bill. He explained, “the Senate might as well try to legislate water to run uphill as to establish mathematical truth by law.”

An irrational ending for pi

Goodwin’s bill died, as did Goodwin’s re-examination of pi. Accordingly, pi as we know it—the infinite and irrational but utterly constant geometric essence of a circle—remains as such. Now that you have math on the brain, try solving these tricky math riddles.


Lauren Cahn
Lauren Cahn is a New York–based writer whose work has appeared regularly on Reader's Digest and in a variety of other publications since 2008. She covers life and style, popular culture, law, religion, health, fitness, yoga, entertaining and entertainment. Lauren is also an author of crime fiction, and her first full-length manuscript, "The Trust Game," was short-listed for the 2017 CLUE Award for emerging talent in the genre of suspense fiction.