Parallel (geometry): Difference between revisions

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imported>Miguel Adérito Trigueira
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imported>Miguel Adérito Trigueira
m (Unicode for vertical lines. Removed overlink to geometry better served by previous link to Euclidean geometry)
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In [[Euclidean geometry]]:
In [[Euclidean geometry]]:


'''Parallel''' (symbolized by two lines '''||''') lines never meet. Two [[geometry]]ic entities are said to be '''parallel''' if they do not [[intersect_(geometry)|intersect]] if projected to infinity. More than one element may be parallel to any number of other elements, which would all be parallel to one another.
'''Parallel''' (symbolized by two adjacent vertical lines '''''') lines never meet. Two geometric entities are said to be '''parallel''' if they do not [[intersect_(geometry)|intersect]] if projected to infinity. More than one element may be parallel to any number of other elements, which would all be parallel to one another.


Thus two [[line_(geometry)|lines]] are parallel if they do not cross at any [[point_(geometry)|point]].
Thus two [[line_(geometry)|lines]] are parallel if they do not cross at any [[point_(geometry)|point]].

Revision as of 03:55, 15 August 2008

In Euclidean geometry:

Parallel (symbolized by two adjacent vertical lines ) lines never meet. Two geometric entities are said to be parallel if they do not intersect if projected to infinity. More than one element may be parallel to any number of other elements, which would all be parallel to one another.

Thus two lines are parallel if they do not cross at any point. Similarly two planes are said to be parallel if they do not intersect at any line.

The following demonstrates parallel lines:

If a line AB is parallel to CD 
and AB is parallel to EF 
then CD is parallel to EF 

The following demonstrates parallel planes:

If a plane ABC is parallel to DEF 
and ABC is parallel to GHI
then ABC is parallel to GHI