Difference between revisions of "Circumference"

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'''Circumference''' typically refers to the distance around a [[circle]], though it may refer to the distance around any [[closed curve]] like an [[ellipse]], though calculating the circumference of an [[ellipse]] is moderately harder than calculating the circumference of a circle. The '''circumference''' of a [[circle]] is typically solved by <math>\pi \cdot d</math> where <math>d</math> represents a circle's [[diameter]], though <math> \pi \cdot 2 r </math> certainly works as well.
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'''Circumference''' is essentially a synonym for [[perimeter]]: for a given [[closed curve]] in the [[plane]], it is the distance one travels in a complete circuit of the curve.  The term circumference is most frequently used to refer to the distance around a [[circle]], though it may refer to the distance around any [[smooth]] curve, while the term perimeter is typically reserved for [[polygon]]s.
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In a circle of [[radius]] <math>r</math> and [[diameter]] <math>d = 2r</math>, the circumference <math>C</math> is given by <math>C = \pi \cdot d = 2\pi \cdot r</math>.  Indeed, the [[constant]] <math>\pi</math> ([[pi]]) was originally defined to be the [[ratio]] of the circumference of a circle to the length of its diameter.
  
  
  
 
==See also==
 
==See also==
* [[Cube]]
 
* [[Parallelepiped]]
 
* [[Parallelogram]]
 
* [[Polygon]]
 

Revision as of 09:32, 13 July 2007

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Circumference is essentially a synonym for perimeter: for a given closed curve in the plane, it is the distance one travels in a complete circuit of the curve. The term circumference is most frequently used to refer to the distance around a circle, though it may refer to the distance around any smooth curve, while the term perimeter is typically reserved for polygons.

In a circle of radius $r$ and diameter $d = 2r$, the circumference $C$ is given by $C = \pi \cdot d = 2\pi \cdot r$. Indeed, the constant $\pi$ (pi) was originally defined to be the ratio of the circumference of a circle to the length of its diameter.


See also