For all of our readers who are engineers, mathematicians, or simply have an affinity for the *constant* appeal of Pi, then this day is for you. March 14th is designated as Pi Day.

Pi, as we all learned in school (and are reminded every March 14), is denoted by the Greek letter π. As many of us learned in school, Π, is defined as the ratio of a circle’s circumference to its diameter. It is the English spelling of the Greek letter and is pronounced in English as “pie.” Its constant value is used in math that represents the ratio of a circumference of a circle to its diameter. Π is an irrational number, which means that it is a real number that cannot be expressed by a simple fraction. Computers have calculated it out past 22 trillion digits and longer 3.141592653589793238462643383279502…, going on forever, infinity.

## Why is Pi Day Celebrated on March 14?

While Π is an infinite number, you usually see it shortened to two decimal points — 3.14. That’s why March 14 (3rd month, 14th day) is the official Pi Day! The idea of celebrating it on this day was first introduced by physicist Larry Shaw in 1988 at the San Francisco Exploratorium. The U.S. House of Representatives officially recognized March 14th as National Pi Day in 2009. The day coincides with another special event – the birthday of physicist Albert Einstein, adding to the scientific significance of the date. Today, many people who celebrate Pi Day also feast on a baked pie, sometimes even pizza pie.

The **International Day of Mathematics** is also celebrated on this day, highlighting the infinite nature of Π and its significance in various fields from engineering to space exploration.

## Pie for Pi

Eating pie on Pi Day is a playful tradition and a pun on the word ‘pi’. The connection comes from the fact that ‘pi’ and ‘pie’ are homophones in English, meaning they sound the same but have different meanings. Moreover, the circular shape of many pies serves as a tribute to the geometric origins of the number Pi, which is the ratio of a circle’s circumference to its diameter. This tradition adds a fun, tangible element to a day dedicated to an abstract mathematical concept. The variety of pies, from sweet to savory, also offers a way for everyone to participate in the celebration, regardless of their culinary preferences.

## Other Pi Day Activities

On Pi Day, there are a myriad of activities that cater to different age groups, interests, and skill levels.

**For the Classroom**: Teachers can incorporate a wide range of educational activities that make learning about Pi fun and interactive:

- Creating paper chains or Plates with varying digits of Pi
- Organizing pizza parties that play on the ‘pi’ and ‘pie’ homophone
- Using tools such as string and ruler for students to discover Pi themselves

However, the activities aren’t limited to the classroom. They can extend to:

- Songs and art projects that explore the concept of Pi
- Puzzles and logic games that challenge and engage
- Pi-themed costume parties or photo booths for a fun spin

Technology can also play a key role in Pi Day activities. NASA’s Pi Day challenge, for example, allows participants to apply their knowledge of Pi in a real-world context. From memorizing the digits of Pi to calculating the volume of a cylinder, there’s a Pi Day activity for everyone. Whether you’re a math enthusiast or just looking for a fun way to celebrate, Pi Day offers endless possibilities for exploration and discovery.

## How We Use 3.14 Today

So, how does Π=3.141592 6535 8979323846 2643383279 5028841971 6939937510 5820974944 5923078164 0628620899 8628034825 3421170679….. fit into today’s world?

It does, in fact, in many ways. This mathematical constant has a big role in virtually every industry. Take aerospace for example. Engineers in the aerospace industry use Pi for what is known as actuators. Actuators control the flaps that move on aircraft wings and tails or the parts that open and close valves on jet engines. Controllers send signals to electric motors, telling them how fast they need to spin to make the actuators move.

NASA Engineers use Pi to put spacecraft into orbit around other planets. To do this, they have to slow down the spacecraft just enough and at exactly the right time for it to get pulled into orbit by the planet’s gravity. In the search for planets outside of our solar system, Pi is used in the equations that would help us characterize these foreign planets. These exoplanets are characterized by their density, which gives us an idea if a planet is mostly made of gas or rocks and the formula for density just happens to have pi in it.

The constant is also used in various industries. These include, but are not limited to:

- Construction, Cities and Territories
- Consumer Packaged Goods & Retail
- Life Sciences & Healthcare
- Energy & Materials
- Transportation &Mobility

Whatever your engineering or mathematical preferences are, enjoy Pi Day, especially if it includes a “pie”.