Changes

'''Pi''', or '''Archimedes' constant''', is perhaps the most important [[mathematics|mathematical]] constant in all of [[mathematics]] and engineering.  It is defined as the [[ratio]] of the [[circumference]] of a [[circle]] to its [[diameter]], and represented by the 16th letter of the Greek alphabet, '''<big><math>\pi</math></big>'''.  It was first used with its current meaning in 1706 by a Welsh mathematician William Jones.<ref name="hist">{{cite web

'''Pi''', or '''[[Archimedes]]' constant''', is perhaps the most important [[mathematics|mathematical]] constant in all of [[mathematics]] and engineering.  It is defined as the [[ratio]] of the [[circumference]] of a [[circle]] to its [[diameter]], and represented by the 16th letter of the Greek alphabet, '''<big><math>\pi</math></big>'''.  It was first used with its current meaning in 1706 by a Welsh mathematician William Jones,<ref name="hist">{{cite web

| url = http://www-groups.dcs.st-and.ac.uk/history/HistTopics/Pi_through_the_ages.html  

| url = http://www-groups.dcs.st-and.ac.uk/history/HistTopics/Pi_through_the_ages.html  

| title = A history or Pi

| title = A history or Pi

| accessdate = 2012-02-11}}</ref>, who selected  '''<big><math>\pi</math></big>''' because it is the first letter of the Greek word for [[perimeter]] (''περίμετρος''), i.e. the circumference of a circle is its perimeter.  A Swiss mathematician, [[Leonhard Euler]], brought the concept into general use in 1737.

| accessdate = 2012-02-11}}</ref> who selected  '''<big><math>\pi</math></big>''' because it is the first letter of the Greek word for [[perimeter]] (''περίμετρος''), i.e. the circumference of a circle is its perimeter.  A Swiss mathematician, [[Leonhard Euler]], brought the concept into general use in 1737.

<big><math>\pi</math></big> is referenced in the [[Bible]], literature, and even as the title of a movie.  It is central to the most famous identity in all of mathematics:  [[Euler's Formula|Euler's Identity]].

<big><math>\pi</math></big> is referenced in the [[Bible]], literature, and even as the title of a movie.  It is central to the most famous identity in all of mathematics:  [[Euler's Formula|Euler's Identity]].