Difference between revisions of "Geometry"

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'''Geometry''' is the field of [[mathematics]] dealing with figures in a given space.
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'''Geometry''' is the field of [[mathematics]] dealing with figures in a given [[space]]. It is one of the two oldest branches of mathematics, along with [[arithmetic]] (which eventually branched into [[number theory]] and [[algebra]]). The geometry usually studied is
  
== Introductory Topics ==
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==Introductory Videos==
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https://youtu.be/51K3uCzntWs?t=842 \\
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https://youtu.be/j3QSD5eDpzU
  
* [[Area]]
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== Euclidean Geometry ==
* [[Circle]]s
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{{main|Euclidean geometry}}
* [[Similar figure]]s
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The most common type of geometry used in pre-[[college|collegiate]] [[mathematics competitions]] is Euclidean geometry. This type of geometry was first formally outlined by the Greek [[mathematician]] [[Euclid]] in his book ''[[The Elements]]''.
* [[Triangle]]s
 
* [[Parallel]] lines
 
* [[Quadrilateral]]s
 
* [[Polygon]]s
 
* [[Power of a point]]
 
* [[Triangle inequality]]
 
  
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===Parallel Postulate===
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{{main|Parallel Postulate}}
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The fifth [[postulate]] stated in the book, equivalent to the following statement,
  
== Intermediate Topics ==
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:''“Through any line and a point not on the line, there is exactly one line passing through that point parallel to the line”''
  
* [[Angle bisector theorem]]
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was the subject of a controversy for many centuries, with many attempted proofs. It is much less simple than the other postulates, and more wordy. This postulate is the basis of Euclidean geometry.
* [[Area]]
 
* [[Mass Point Geometry]]
 
* [[Ptolemy's Theorem]]
 
* [[Cyclic quadrilateral]]s
 
* [[Stewart's Theorem]]
 
* [[Trigonometry]]
 
  
== Olympiad Topics ==
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== Non-Euclidean Geometry ==
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Non-Euclidean geometry are geometries in which the fifth postulate is altered. Types of non-Euclidean geometry include:
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*[[Elliptical geometry]]
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*[[Hyperbolic geometry]]
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== Student Guides to Geometry ==
  
* [[Brocard points]]
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* [[Geometry/Introduction | Introductory Geometry]]
* [[Collinearity]]
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* [[Geometry/Intermediate | Intermediate Geometry]]
* [[Complex numbers]]
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* [[Geometry/Olympiad | Olympiad Geometry]]
* [[Concurrency]]
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* [[Geometry/Resources | Geometry Resources]]
* [[Directed angles]]
 
* [[Geometric inequalities]]
 
* [[Homothecy]]
 
* [[Inversion]]
 
* [[Isogonal conjugates]]
 
* [[Projective geometry]]
 
* [[Radical axis]]
 
* [[Transformations]]
 
* [[Trigonometry]]
 
  
== Other Topics of Interest ==
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==Main Concepts==
* The notion of [[dimensions]]
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* The notion of [[dimension]]s is fundamental to geometry. [[N-space]] is a term related to this concept.
** [[n-space]]
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*A [[point]] is a geometric structure with no area, length, width, or dimension. Its only property is space. It is said to be zero-dimensional.
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*A [[line]] is generally taken to mean a straight line, which is the locus of points on the [[Cartesian plane]] satisfying a [[linear]] [[function]]. It has length and position, but no other properties. It is one-dimensional. A [[line segment]] means a finite segment of a line, while a [[ray]] is a line infinitely extending in only one direction.
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*A [[plane]] is a line but in a Cartesian space. It as length, width, and position. It is two-dimensional. The point/line/plane sequence can be extended to spaces and higher dimensions.
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*An [[angle]] is a structure formed by the intersection two [[ray]]s at their endpoints. It is measure in either [[degree]]s or [[radian]]s, though the less-common [[Système international|metric]] unit [[gradian]] is also used.
  
== Resouces ==
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== See Also ==
Listed below are various geometry resources including books, classes, websites, and computer software.
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* [[Point]]
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* [[The Elements]]
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* [[Topology]]
  
=== Books ===
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[[Category:Geometry]] [[Category:Mathematics]] [[Category:Topology]]
* Introductory
 
** ''Introduction to Geometry'' by Richard Rusczyk [http://www.artofproblemsolving.com/Books/AoPS_B_Item.php?page_id=9 (details)]
 
* Intermediate
 
** ''Challenging Problems in Geometry'' by Posamentier, Salkind [http://www.amazon.com/exec/obidos/ASIN/0486691543/artofproblems-20 (details)]
 
* Olympiad
 
** ''Advanced Euclidean Geometry'' by Posamentier [http://www.keypress.com/catalog/products/supplementals/Prod_AdvancedEuclidean.html (details)]
 
** ''Geometry Revisited''  by Coxeter and Greitzer [http://www.amazon.com/exec/obidos/ASIN/0883856190/artofproblems-20 (details)]
 
** [http://www-math.mit.edu/~kedlaya/geometryunbound/gu-060118.pdf Geometry Unbound]
 
 
 
=== Websites ===
 
All of these links are outside of [AoPSWiki].
 
* [http://www.cut-the-knot.org/geometry.shtml Cut-the-Knot's Geometry Section]
 
* [http://www.ics.uci.edu/~eppstein/junkyard/ The Geometry Junkyard]
 
* [http://www.artofproblemsolving.com/Forum/index.php?f=4 AoPS/Mathlinks Olympiad Geometry Section]
 
 
 
=== Software ===
 
These are all outside links.
 
* [http://www.geometer.org/geometer/ Geometer]
 
* [http://www.keypress.com/sketchpad/ The Geometer's Sketchpad]
 
* [http://www.mit.edu/~ibaran/kseg.html KSEG]
 
 
 
=== Miscellaneous ===
 
* Introductory
 
** [[Introduction to Geometry Course]] [http://www.artofproblemsolving.com/Classes/AoPS_C_ClassesS.php#beggeom (details)]
 
 
 
 
 
== See also ==
 
* [[Table of Contents]]
 
* [[Mathematics news]]
 

Latest revision as of 07:59, 25 September 2020

Geometry is the field of mathematics dealing with figures in a given space. It is one of the two oldest branches of mathematics, along with arithmetic (which eventually branched into number theory and algebra). The geometry usually studied is

Introductory Videos

https://youtu.be/51K3uCzntWs?t=842 \\ https://youtu.be/j3QSD5eDpzU

Euclidean Geometry

Main article: Euclidean geometry

The most common type of geometry used in pre-collegiate mathematics competitions is Euclidean geometry. This type of geometry was first formally outlined by the Greek mathematician Euclid in his book The Elements.

Parallel Postulate

Main article: Parallel Postulate

The fifth postulate stated in the book, equivalent to the following statement,

“Through any line and a point not on the line, there is exactly one line passing through that point parallel to the line”

was the subject of a controversy for many centuries, with many attempted proofs. It is much less simple than the other postulates, and more wordy. This postulate is the basis of Euclidean geometry.

Non-Euclidean Geometry

Non-Euclidean geometry are geometries in which the fifth postulate is altered. Types of non-Euclidean geometry include:

Student Guides to Geometry

Main Concepts

  • The notion of dimensions is fundamental to geometry. N-space is a term related to this concept.
  • A point is a geometric structure with no area, length, width, or dimension. Its only property is space. It is said to be zero-dimensional.
  • A line is generally taken to mean a straight line, which is the locus of points on the Cartesian plane satisfying a linear function. It has length and position, but no other properties. It is one-dimensional. A line segment means a finite segment of a line, while a ray is a line infinitely extending in only one direction.
  • A plane is a line but in a Cartesian space. It as length, width, and position. It is two-dimensional. The point/line/plane sequence can be extended to spaces and higher dimensions.
  • An angle is a structure formed by the intersection two rays at their endpoints. It is measure in either degrees or radians, though the less-common metric unit gradian is also used.

See Also