π (Pi)
What Is Pi (π)?
Pi (pronounced “pie”) is a special number in math that helps us measure circles. No matter how big or small a circle is, the distance around the circle (the circumference) is always a little more than 3 times its width (the diameter). That “little more” is where pi comes in.
What’s the Value of Pi?
Pi is about 3.14, but it’s actually a number that goes on forever without repeating: 3.14159…
Since it never ends, we usually just use 3.14 for easy math.
Why Is Pi Important?
Pi shows up whenever we work with circles:
To find the circumference: C = π × diameter
To find the area: A = π × radius² (radius is half the diameter)
Scientists, engineers, and even astronauts use pi to build bridges, design rockets, and figure out orbits!
Fun Facts About Pi
Pi Day is on March 14 (3/14) because the date looks like 3.14.
People have memorized tens of thousands of digits of pi as a challenge!
Pi is an irrational number, which means it can’t be written as a simple fraction.