Today is Pi Day, founded by Physicist Larry Shaw in 1988, and celebrated in countries that follow the month/day (m/dd) date format, because the digits in the date, March 14 or 3/14, are the first three digits of π (3.14).

One of the oldest and the most recognized mathematical constant in the world, π is the ratio of any circle’s circumference to its diameter. Its value is approximately equal to 3.14159265. It is an irrational number,Source: MometrixSource: Mometrix which means it cannot be expressed as a ratio of whole numbers, and its decimal representation never ends or repeats.

What else is notable about March 14?

On this day on 1927, the American Society of Civil Engineers elected Elsie Eaves as an associate member. She is the first woman elected to the society.

Albert Einstein was born on this day in 1879.

Astronauts Frank Borman (1928) and Eugene Cernan (1934) were also born on March 14.

Mark the day by taking this quiz and reciting up to 150 digits of pi using your memory. Or try your hand at solving the same problems NASA scientists and engineers do using pi.

Or just have some pie.

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