Editing Cylinder (section)

==Prisms==

[[File:TychoBrahePlanetarium-Copenhagen.jpg|thumb|[[Tycho Brahe Planetarium]] building, Copenhagen, is an example of a truncated cylinder]]

A ''solid circular cylinder'' can be seen as the limiting case of a [[regular polygon|{{mvar|n}}-gonal]] prism where {{math|''n''}} approaches [[infinity]]. The connection is very strong and many older texts treat [[Prism (geometry)|prisms]] and cylinders simultaneously. Formulas for surface area and volume are derived from the corresponding formulas for prisms by using inscribed and circumscribed prisms and then letting the number of sides of the prism increase without bound.<ref>{{citation |first1=H.E. |last1=Slaught |author-link=Herbert Ellsworth Slaught |first2=N.J. |last2=Lennes |title=Solid Geometry with Problems and Applications |edition=Rev. |year=1919 |publisher=Allyn and Bacon |url=http://www.gutenberg.org/files/29807/29807-pdf.pdf |pages=79–81}}</ref> One reason for the early emphasis (and sometimes exclusive treatment) on circular cylinders is that a circular base is the only type of geometric figure for which this technique works with the use of only elementary considerations (no appeal to calculus or more advanced mathematics). Terminology about prisms and cylinders is identical. Thus, for example, since a ''truncated prism'' is a prism whose bases do not lie in parallel planes, a solid cylinder whose bases do not lie in parallel planes would be called a ''truncated cylinder''.

From a polyhedral viewpoint, a cylinder can also be seen as a [[dual polyhedron|dual]] of a [[bicone]] as an infinite-sided [[bipyramid]].

{{UniformPrisms}}