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In plane geometry, the '''perimeter''' of a 2-dimensional object is equal to the length of the object's boundary. For example, the perimeter of a [[polygon]] is the sum of the lengths of its sides.  The perimeter of a circle is called a [[circumference]], and is the circle's [[diameter]] multiplied by [[pi]].

In [[Plane_geometry|plane geometry]], the '''perimeter''' of a [[Closed_(topology)|closed]], [[Bounded|bounded]], geometric shape with [[Nonempty|nonempty]] [[Interior|interior]] is equal to the [[Length|length]] of the object's [[Boundary|boundary]]. Thus, familiar geometric shapes such as [[Circle|circles]] and [[Polygon|polygons]] have a perimeter. [[Line_segment|Line segments]] and [[Sierpinski_gasket|Sierpinski gaskets]] do not have a perimeter since they have an empty interior (all the other properties are satisfied).

 

The perimeter of a [[polygon]] is the sum of the lengths of its sides.  The perimeter of a circle is called a [[circumference]], and is the circle's [[diameter]] multiplied by [[pi]].

[[Category:Geometry]]

[[Category:Geometry]]