{{Unreferenced|date=December 2007}}
The '''aspect ratio''' of a two-dimensional shape is the ratio of its longer dimension to its shorter dimension. It is also applied to two characteristic dimensions of a three-dimensional shape, especially for the longest and shortest 'axes' or for symmetrical objects (''e.g''. rods) that are described by just two measures (''e.g''. length and diameter). In such cases, the aspect ratio may evaluate to a value less than one (''e.g''. consider very short and very long rods). The aspect ratio of a [[torus]] is the ratio of the major axis ''R'' to the minor axis ''r''.

In aviation, the aspect ratio of aircraft tapered wings is found by dividing the square of the wing span {b} by the total wing area (S):

AR = b²/S

If the wing has a constant [[Chord (aircraft)|chord]], the aspect ratio is the result of dividing the wingspan (b) by the value of the chord (c):

AR = b/c

Similarly, if the value of the mean [[Chord (geometry)|geometric chord]] is known, the aspect ratio is the result of dividing the wingspan by the value of the mean geometric chord:

AR = b/c_mean

{{Wiktionarypar|aspect ratio}}

The term is most commonly used with reference to:
*[[aspect ratio (image)]]
*[[computer display standard]]
*[[paper size]]
*[[pixel aspect ratio]]
*[[tire sizing]]
*[[aspect ratio (wing)]] of [[aircraft]] or [[bird]]s
*[[Astigmatism|aspect ratio (optics)]] of a lens diameter or longest dimension relative to its thickness

[[Image:Aspect ratio compare.svg]]

==See also==
* [[Golden ratio]]
* [[Ratio]]

[[Category:Numerology]]

[[ko:가로세로비]]
[[it:Aspect ratio]]
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[[zh:縱橫比]]