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[[File:Capsule_geometry.svg|right|thumb|300px]]

A '''capsule''', also known as a '''[[Stadium (geometry)|stadium]] of revolution''', is a basic three dimensional geometric shape. It consists of a cylinder with hemispherical ends.<ref>{{cite web|url=http://mathworld.wolfram.com/Capsule.html |title=Capsule |publisher=Mathworld.wolfram.com |date=2005-10-20 |accessdate=2013-01-31}}</ref> Another name for this shape is "spherocylinder".<ref>{{cite journal|last=Dzubiella|first=Joachim|coauthors=Matthias Schmidt, and Hartmut Löwen|title=Topological defects in nematic droplets of hard spherocylinders|journal=Physical Review E|year=2000|volume=62|page=5081|doi=10.1103/PhysRevE.62.5081}}</ref> The shape is used for [[Pressure vessel#Cylindrical vessel with hemispherical ends|containers for pressurised gasses]].

==Formulas==
The volume of a capsule is calculated by the formula <math>\pi r^2 \left (\frac{4}{3}r + a \right )</math> where <math>r</math> is the radius of the cylinder and hemispheres and <math>a</math> is the length of the cylindrical part.

The surface area formula is <math>2 \pi r (2r + a)</math> where <math>r</math> is the radius of the cylinder and hemispheres and <math>a</math> is the length of the cylindrical part.<ref>{{cite web|url=http://www.calculatorsoup.com/calculators/geometry-solids/capsule.php |title=Capsule Calculator |publisher=Calculatorsoup.com |date= |accessdate=2013-02-18}}</ref>

==References==
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[[Category:Elementary shapes]]


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