Explanation:
In geometry, a frustum (plural: frusta or frustums)
is the portion of a solid (normally a cone or pyramid) that lies between two parallel planes cutting it.
The term is commonly used in computer
graphics to describe the
three-dimensional region which is visible on the screen, the 'viewing frustum',
which is formed by a clipped pyramid; in particular, frustum culling is a method of hidden surface determination.
In the aerospace
industry, frustum is the common term for the fairing between two stages of a multistage rocket (such as the Saturn V), which is shaped like a truncated cone.
Surface area
The surface area of a right circular cone frustum is
http://en.wikipedia.org/wiki/Frustum
The
above explanation is copied from Wikipedia, the free encyclopedia and is
remixed as allowed under the Creative Commons Attribution- ShareAlike 3.0 Unported
License.
(Our solved example in mathguru.com uses the below concept. This
is our own explanation, it is not taken from Wikipedia.)
Curved surface area of frustum of a cone
is given by
A =l (r_{1 }+
r_{2})
Where
l is the
slant height
r_{1}
and r_{2} are radii of 2 circular ends