What Is Pi?

If you look on your calculator, you can see Pi as looking like a little table shape, and will always give the same constant number. In education you may know it as 3.14, or 3.14159..., but did you know it is infinite? It is an irrational number, which means roughly in Surds they cannot be square rooted and they cannot be written as a simple fraction. As a decimal it is never ending and I wouldn`t want to use bus stop division on that sum!

How was it found? Well, mathematicians found the ratio of the circumference to the diameter and it was called Pi after the Greek word for perimeter - perimitros. No matter how big or small the circle, the ratio of circumference and diameter confrom to Pi and the number 3.14....

The cool thing about Pi as within our planet, any circular object can be theoretically calculated with Pi. From crop circles, footballs, hats, wedding rings, dinner plates, golf balls and the list goes on. Using the two formulas for area and circumference always work.

• Pi x radius squared for area.
• Pi x diameter for circumference.

I have told my students not to use Pi on anything that is not circular. Yes, it can be used on a cylinder, but only the ends!