Rectilinear angle (geometry): Difference between revisions

From Citizendium
Jump to navigation Jump to search
imported>Miguel Adérito Trigueira
(Added diagram, link to Euclidean geometry)
imported>Miguel Adérito Trigueira
(3 intermediate revisions by the same user not shown)
Line 1: Line 1:
[[Image:angle (geometry).png|frame|Diagram showing the terminology of an angle including arms (in red), vertex (in light blue) and angle (in green)]]
{{subpages}}
 
{|
|-
|
[[Image:angle (geometry).png|frame|left|Diagram showing the terminology of an angle including arms (in red), vertex (in light blue) and angle (in green)]]


In [[Euclidean geometry]]:
In [[Euclidean geometry]]:
Line 9: Line 14:
There are various special types of angles:
There are various special types of angles:
*[[right angle (geometry)|right angle]]
*[[right angle (geometry)|right angle]]
*[[obtuse angle (geometry)|obtuse angle]]
*[[#Obtuse angle|obtuse angle]]
*[[acute angle (geometry)|acute angle]]
*[[#Acute angle|acute angle]]
*[[#Straight angle|straight angle]]
 
 
|-
|
==Obtuse angle==
[[Image:Obtuse angle (geometry).png|frame|left|Diagram showing an obtuse angle (in green)]]
An '''obtuse angle''' is one where the magnitude of the angle is greater than a right angle, but less than a [[#Straight angle|straight angle]].
 
|-
|
==Acute angle==
[[Image:Acute angle (geometry).png|frame|left|Diagram showing an acute angle (in green)]]
 
An '''acute angle''' is one where the magnitude of the angle is less than a right angle.
 
|-
|
==Straight angle==
[[Image:Straight angle (geometry).png|frame|left|Diagram showing a straight angle (in green)]]
A '''straight angle''' is the angle formed on a straight line. It is equal on both sides of the line. It is equal to the sum of two right angles.
 
|}

Revision as of 06:20, 22 October 2008

This article is developed but not approved.
Main Article
Discussion
Related Articles  [?]
Bibliography  [?]
External Links  [?]
Citable Version  [?]
 
This editable, developed Main Article is subject to a disclaimer.
Diagram showing the terminology of an angle including arms (in red), vertex (in light blue) and angle (in green)

In Euclidean geometry:

A rectilinear angle or angle is the "steepness" between two straight lines. The point at which the lines intersect is called the vertex. The parts of the line that extend from the vertex and surround the "steepness" are called the arms.

This angle is measured in degrees (parts of 360). This angle can also be measured in radians.

There are various special types of angles:


Obtuse angle

Diagram showing an obtuse angle (in green)

An obtuse angle is one where the magnitude of the angle is greater than a right angle, but less than a straight angle.

Acute angle

Diagram showing an acute angle (in green)

An acute angle is one where the magnitude of the angle is less than a right angle.

Straight angle

Diagram showing a straight angle (in green)

A straight angle is the angle formed on a straight line. It is equal on both sides of the line. It is equal to the sum of two right angles.