# The "Math Pi Symbol"

We know the math pi symbol can be very confusing for some math students, but don't worry, its not that bad.

 The pi symbol is really just a letter of the Greek alphabet.  It's pronounced "pie" but written as pi. The symbol is:  π.  In math, π is always equal to the number 3.1415926... The number goes on forever! And it never repeats the patter, it is alsways different. To make sure you know the difference between pi and pie, look below:
 A Delicious Dessert The Greek Letter Pi

 Understanding why we need Pi

Pi represents the circumference of a circle with radius equal to 0.5.  Therefore, pi will be used a lot for formulas involving circles.  Look at the figure at the right.

 The distance around this circle equals pi.  In other words, if the measurements were in miles, we would have to walk a little more than 3.14 miles to walk around the outside of our circle.  Think about it as walking around a track - a track that is a perfect circle.  Two important formulas: Area = πr2    Circumference = 2πr

 Facts about "The Math Pie Symbol"
• π = 3.14159265358979323846264338327950288419716939937510...
 π is the lowercase Greek letter pi - the 16th letter of the alphabet. π is an irrational number, meaning its decimals goes on forever... Pi occurs in many scientific formulas, like DNA, navigation, & more. The Babylonians found the first known value of pi in 2000 BC (25/8). The Bible uses pi with a value of 3 instead of 3.1415... Ahmes the scribe was the first to write about pi in 1650 BC.