CCSS: 6.EE.A.2.C, 7.EE.B.3, MP1, MP6

TEKS: 6.3D, 6.7D, 7.3A, 7.3B

By the Numbers: All About Pi

Dividing a circle’s circumference by its diameter always yields the same number: pi. This constant equals about 22/7, or 3.14. Pi is an infinite decimal—its digits go on forever. People have calculated its never-ending numbers since antiquity. Pi even has its own holiday! Every year on March 14 (3/14), math lovers celebrate the irrational number by holding competitions to recite its digits; writing “pi-kus” (haikus about pi); and eating delicious pies.

Read on to learn more out about this irrational number. Then plug in the numbers into the equation below to reveal a final fact.


Adoc-Photos/Corbis via Getty Images

Number of sides of the polygon that Greek mathematician Archimedes used to estimate pi’s value 2,000 years ago— before decimals existed!



Minimum number of digits of pi needed in the calculations that keep the International Space Station in orbit


Bettmann/Getty Images

Year Albert Einstein was born on Pi Day!



Guinness World Records

Hours spent reciting pi—to 70,000 decimal places—by 25-year-old student Rajveer Meena from Vellore, India. It earned him a world record shortly after Pi Day in 2015.


Number of digits in pi before the appearance of a zero