Circumference (geometry)
The circumference of a flat figure, which is bounded by a line , denotes the length of its boundary line.
The formula for the circumference is:

 stands for the scope
 for the radius of the circle ,
 for the circle number with the value 3.14159265… and
 for the circle diameter .
The circumference of a polygon is the sum of its side lengths .
If the boundary line of the figure is described by a closed, piecewise smooth parameter curve with
 ,
so the circumference can be calculated using the following integral :
 .
Web links
Wiktionary: scope  explanations of meanings, word origins, synonyms, translations
 Eric W. Weisstein : Perimeter . In: MathWorld (English).