Length: Difference between revisions

Measurement has been important ever since humans settled from nomadic lifestyles and started using building materials, occupying land and trading with neighbours. As trade between different places increased, the need for standard units of length increased. And later, as society has become more technologically oriented, much higher accuracy of measurement is required in an increasingly diverse set of fields, from micro-electronics to interplanetary ranging.<ref>History of Length Measurement, [http://resource.npl.co.uk/docs/educate_explore/posters/bg_historyoflength_poster.pdf National Physical Laboratory] {{Webarchive|url=https://web.archive.org/web/20131126043209/http://resource.npl.co.uk/docs/educate_explore/posters/bg_historyoflength_poster.pdf |date=2013-11-26 }}</ref>

 

 

== Use in mathematics ==

=== Euclidean geometry ===

{{main|Euclidean geometry}}

 

In a [[triangle]], the length of an [[Altitude (triangle)|altitude]], a line segment drawn from a vertex [[perpendicular]] to the side not passing through the vertex (referred to as a [[Base (geometry)|base]] of the triangle), is called the height of the triangle.