Ways to Celebrate National Pi(e) Day


A berry pie with top crust in the shape of the pi symbol for National Pi Day.I’m what you would consider “mathematically challenged.” Math is not a language I’m fluent in, and I really struggled with it all through school (Why did I take Trig my senior year of high school?). Big sigh of relief when I passed the most basic college math class. Oddly enough, geometry wasn’t as challenging for me for some reason.

Although I couldn’t tell you what “x” equals unless you’re talking about a punk rock band from the 80s, I do, however, remember 3.14. It’s the one thing that stuck. Maybe because it’s the symbol for pi, and I love to eat pie . . . so, an easy association to remember.

What is Pi?

Pi is the most well-known mathematical constant and how we calculate the ratio of the circumference of a circle to its diameter. The distance around the edge of a circle is a little more than three times the distance across. Hence, 3.14.

Pi Fun Facts

  • The symbol for pi has been used for over 250 years. It is represented by the Greek symbol π. Calculating pi has been around a lot longer though — like 4,000 years ago longer.
  • The exact number of pi can’t be calculated, so we can never find the exact circumference of a circle. Therefore, there is no such thing as a “perfect circle.”
  • Pi is an irrational number, so don’t argue with it. Just kidding. An irrational number has a decimal with no end and no repeating pattern.
  • Pi is a part of Egyptian mythology, and it is believed that the Giza pyramids were built on the principle of pi.
  • It wasn’t always called pi. Prior to the 18th century, it was referred to as “the quantity which when the diameter is multiplied by it, yields the circumference.” A bit wordy, don’t you think?
  • The physicist Larry Shaw started celebrating March 14th as Pi Day in 1988 at the San Francisco Exploratorium Museum. And it is still going strong today!

What is Pie?

A pie is a sweet or savory baked dish typically with a top and base of pastry (crust).

Pie Fun Facts

  • Invented by the Egyptians and can be traced back to 6000 BC.
  • Ancient Greeks had pastry chefs in the 5th century BC, separate from the baker trade.
  • Ancient Romans used pie crust to preserve meats, but it was not intended to be eaten.
  • Elizabeth I is allegedly the first to try cherry pie.
  • The pie crust was referred to as “placenta” in Ancient Rome, and as “coffin” in Medieval Britain. Not the most appetizing of terms.
  • Apple pie dates back to 14th Century England with the recipe printed by Geoffrey Chaucer (yes, that Chaucer!).
  • The association of America and apple pie dates back to WWII when soldiers were asked why they were off to battle, the response was “for mom and apple pie.”

Ways to Celebrate Pi(e) Day

Here are a couple of fun and easy ways to celebrate Pi(e) Day with the kiddos, and they’ll get some valuable STEM lessons in the process!

Cutting Pi(e)

  • Buy a pie, any pie, and measure it to find the diameter and circumference which will equal 3.14. You’ll need only string and scissors for this project, and your pie of course.
  1. Wrap the string carefully around the circumference of your pie.
  2. Cut the string at exactly one circumference of the pie.
  3. Take the string circumference and stretch it across the diameter of your pie.
  4. Cut as many string diameters as you can.
  5. You should end up with three string diameters, plus a little extra, giving you 3 and 1/7 pieces, or 3.14.
  6. Eat a piece of pie (or two) to celebrate your accomplishment!

Pi(e) Graph

  • Take any cylindrical objects: mini pie, regular-sized pie, pizza pie, etc. to graph circular ratios. This can demonstrate discovering patterns in nature. You can also use non-food-related objects like a plate, roll of tape, or CD (But where is the fun in that?). You’ll need string, a metric ruler, paper, pencil, and graph paper.
    1. On a piece of paper create a chart with one column showing “object name,” the next column showing “diameter (cm),” and the last column showing “circumference (cm)”:
Object Diameter (cm) Circumference (cm)


2. Measure the diameter of each object and record it on the chart using the metric ruler.

3. Then, wrap your string around the object, measure the circumference, and record it on the chart.

4. On the graph paper, plot the points that represent each object where “x” coordinate is the diameter and “y” coordinate is the circumference.

5. Draw a straight line through the points. Not all the points will touch, but you can estimate the line that the points seem to cluster around.

6. Calculate the slope of the line by choosing any point on the line and dividing the y coordinate by the x coordinate (circumference divided by diameter). You should get a number very close to the value of pi.

Another fun fact: Did you know that 3.14% of sailors are pi-rates?

Share your fun Pi Day activities with us below!