Today is Pi Day! No, we’re not talking peach or apple, we’re talking the mathematical constant pi (π). Why is it Pi Day? The date is 3/14 and the first three digits of pi are 3.14 – a fine reason to celebrate!
We checked in with Dr. Michelle DeLoach, math curriculum specialist and Jill Miller, middle school math specialist, to go full-circle on Pi.
Pi (π) is the ratio of the circumference (the distance around the circle) of any circle to its diameter (the length straight across its middle). So, no matter how big a circle is—whether it’s a deep dish pizza or the hole of a donut—the circumference divided by the diameter will always equal pi, approximated as 3.14 in decimal form.
To calculate the circumference of a circle, use the formula C=πd where d is the diameter of the circle.
Not only can you use pi calculate the circumference of a circle, but you can find the area of a circle with the its radius (the distance from the center to the edge). Use the formula A= πr 2 , where r is the radius, to find out how much space a circle takes up.
Pi never ends and never repeats! To date, pi has been calculated to more than 1 trillion decimal places.
The first 100 digits of pi are...
3.14159265358979323846264338327950288419716939937510
58209749445923078164062862089986280348253421170679
How many digits of pi do you know?
So today, get 3.14 or more of your friends and share a slice of your favorite pie to celebrate this marvel of mathematics. After all, you can’t have pie without Pi.