Right angle (geometry): Difference between revisions
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imported>Hayford Peirce (rewrote the definition to reflect the various definitions that I have listed on the discussion page.) |
imported>Ro Thorpe (added a bit that I'd been thinking of) |
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[[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]], a '''right angle''', symbolised by the L-shaped figure '''∟''', is created when two straight lines meet perpendicularly at 90 degrees to each other. | 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 plus sign, +, consists of two such lines, and so the four angles at its heart are all right angles. | ||
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 16:52, 15 August 2008
_definition.png)
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 plus sign, +, consists of two such lines, and so the four angles at its heart are all right angles.
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