Euclidean geometry

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This editable Main Article is under development and subject to a disclaimer.

[edit intro]

Euclidean geometry is a form of geometry first codified by Euclid in his series of thirteen books, The Elements.

## Concepts[edit]

Some of the concepts used and described in Euclidean geometry are:

* A point is a mathematical object which has a position but neither length nor breadth nor depth.
* line or straight line
* surface
* plane
* plane angle
* rectilinear angle or angle including
* right angle
* obtuse angle
* acute angle
* straight angle
* parallel
* perpendicular
* boundary
* figure
* plane figure
* rectilinear figure
* triangle
* equilateral triangle
* isosceles triangle
* scalene triangle
* right angled triangle
* obtuse angled triangle
* acute angled triangle
* polygon
* cyclic
* square
* oblong
* rhombus
* rhomboid
* trapezia
* circle
* center
* diameter
* semicircle
* trilateral
* quadrilateral
* multilateral
* equilateral
* congruence
* similarity
* rigid motion
* reflection
* rotation
* translation
* dilation