en.wikipedia.org/wiki/Pi

The number π is a mathematical constant, the ratio of a circle's circumference to
its diameter, ... The symbol used by mathematicians to represent the ratio of a
circle's circumference ...

www.reference.com/math/pi-used-5fba050fbb78ef3d

Pi is used to find the circumference and area of a circle. It is also used to find the
volume and surface area of a sphere, cone and cylinder. Pi has applications ...

www.angio.net/pi/whypi.html

Pi (π) is the ratio of the circumference of a circle to its diameter. ... Archimedes
used this trick with 96 sided polygons to correctly estimate Pi to about two digits ...

www.livescience.com/29197-what-is-pi.html

Apr 30, 2013 ... Pi (π), the 16th letter of the Greek alphabet, is used to represent the most widely
known mathematical constant. By definition, pi is the ratio of the ...

mathforum.org/dr.math/faq/faq.pi.html

What is Pi? Who first used Pi? How do you find it? What is it for? How many digits
is it?

www.piday.org/learn-about-pi/

Pi is a constant number, meaning that for all circles of any size, Pi will be the
same. ... The mathematician Archimedes used polygons with many sides to ...

www.mathsisfun.com/numbers/pi.html

pi symbol. Pi (the symbol is the Greek letter π) is: The ratio of the Circumference
... There are many special methods used to calculate π and here is one you can ...

www.enchantedlearning.com/math/pi/

Pi is used in many calculations, including finding the circumference and area of a
circle, and the volume and surface area of a sphere, cone, and cylinder. Pi is ...

lightyears.blogs.cnn.com/2012/03/13/pi-day-how-3-14-helps-find-other-planets-and-more/

Mar 13, 2012 ... iReporter Zeynep Rice made this pie to celebrate Pi Day. .... H/m that's units per
Henry per meter, where a Henry is a unit used in electronics.

www.dkfindout.com/us/math/numbers/pi/

Pi is a useful number that is used in mathematical formulas. It is also written as
the π symbol. The number pi is usually written as 3.14. This has been rounded to
...