411 REFERENCE · Wikibooks
Geometry/Perimeter and Arclength
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
Perimeter of Circle
The circles perimeter can be calculated using the following formula
where the radius of the circle.
Perimeter of Polygons
The perimeter of a polygon with number of sides abbreviated can be calculated using the following formula
.
Arclength of Circles
The arclength of a given circle with radius can be calculated using
where is the angle given in radians.
Arclength of Curves
If a curve in has the parametric form for , then the arclength can be calculated using the following fomula
Derivation of formula can be found using differential geometry on infinitely small triangles.