ARCDC Proudly Celebrates Pi Day
March 2012

Pi Day is a holiday commemorating the mathematical constant π (pi). Pi Day is celebrated on March 14 (or 3-14 in month-day date format), since 3, 1, and 4 are the three most significant digits of π in the decimal form. In 2009, the United States House of Representatives supported the designation of Pi Day.

You have probably heard about π before. Maybe your teacher was talking about it. Maybe you saw it in your math book. Maybe you saw it on television or in a movie. You have heard of it, but do you really know what π is?

Pi is usually something you will hear about when someone is talking about math. Even though π looks like a sign, it is really a number. Why not just write the number? There is a reason that we do not write numbers when we are talking about π. Pi is a number that has no end. It keeps going and going and going! When people need to use π to solve a math problem, they usually just write π as 3.14. That is a close guess of the value of π. If people want to get even closer to the real value of π, they might use 3.14159. It is close to the real value of π, but there are even more numbers that make up π. Some people have spent their whole lives trying to find the true value of π. Now that we have computers, we can use them to get even closer to the true value. In 2002, a group in Japan used a computer to calculate π to more than one trillion decimal places!

That may be interesting, but it still doesn't tell you what π really means. Why would anyone want to use a number that doesn't end? The reason has to do with circles. Pi is a number that is important in understanding circles. Pi is important in finding the circumference, or distance around the outside, or a circle. Pi is also important in finding the area of a circle. Area is the measurement of the space inside a two-dimensional, or flat, object. Pi is also important in finding the volume of circular objects. Volume is the mesadurement of the space inside a three-dimensional object. Spheres, like balls, and cylinders, like soup cans, are both three-dimensional objects that contain circles.

Long ago, people began to study circles to learn more about them. it was easy to see that all circles were similar, but they wanted a way to show it with math. There was one number that was always the same, no matter what the size of the circle. That number was π! To understand π, you also have to know a few things about circles. Draw a circle. Draw a line from one side of the circle, through the middle of the circle, and across to the other side. This line is called the diameter of the circle. It is the distance across a circle. The circumference of a circle is the distance around a circle. it is just like the perimeter of a square or rectangle. The circumference of any circle is π times the diameter of the circle. That means the circumference of the circle is about 3.14 times greater than the diameter of the circle. This is true for any circle, no matter how big or small it is.

Now that you know a little more about π, it should be a lot easier to remember. Pi is a number that has to do with circles. So, the next time you are cutting a slice of apple pie or opening a box of your favorite pizza pie, think about what you know about the number π!

Text researched and compiled by 7th Grade students Kimberly Puckett, Victoria Key, and De'Teidria Adger, and 7th Grade Math Teacher Shayla Hall-Cooper.