Right angle (geometry): Difference between revisions

From Citizendium
Jump to navigation Jump to search
imported>Hayford Peirce
(some positive reformatting; you can't use indented spaces in the Wiki format)
imported>Hayford Peirce
(rewrote the definition to reflect the various definitions that I have listed on the discussion page.)
Line 1: Line 1:
[[Image:Right angle (geometry) definition.png|frame|Diagram showing the definition of a right angle. The green parts are not part of the construction but show that the angles are both 90 degrees and equal to one another]]
[[Image:Right angle (geometry) definition.png|frame|Diagram showing the definition of a right angle. The green parts are not part of the construction but show that the angles are both 90 degrees and equal to one another]]


In [[Euclidean geometry]]:
In [[Euclidean geometry]], a '''right angle''', symbolised by the L-shaped figure '''∟''', is created when two straight lines meet perpendicularly at 90 degrees to each other.
 
A '''right angle''' (symbolised by the L shaped figure '''∟''') is an [[angle]] that the angle made between the arms of the angle is equal to the angle adjacent to it. This angle is ninety degrees.


The right angle bisects the angle of the line into two equal parts.
The right angle bisects the angle of the line into two equal parts.

Revision as of 17:29, 15 August 2008

Diagram showing the definition of a right angle. The green parts are not part of the construction but show that the angles are both 90 degrees and equal to one another

In Euclidean geometry, a right angle, symbolised by the L-shaped figure , is created when two straight lines meet perpendicularly at 90 degrees to each other.

The right angle bisects the angle of the line into two equal parts.

The right angle is demonstrated:

Given a line DC with point B lying on it
Take B as the vertex of angle ABC
If the angle ABC equals the angle ABD
then angle ABC is a right angle,
and so is angle ABD