# Foldable constant rectangle

From Noah.org

## Foldable Constant Rectangle

If you need a foldable rectangle then this is the foldable rectangle for you. A rectangle with these proportions maintains a constant aspect ratio when folded in half perpendicular to the long axis and rotated 90 degrees.

In reasonable parts of the world this is the ratio used for paper. For example, A4 paper.

## Notes

Foldable Constant Rectangle Aspect Ratio = SQRT(2) = 1.414213562373 Video screen Aspect Ratio = 4/3 = 1.333... (Example: 640/480=1.333...)

Given a width of 640 pixels,

Video screen height = 640 / (4/3) = 480 Foldable Constant Rectangle height = 640 / SQRT(2) = 452.54833995939

Difference in height is

(640 / (4/3)) - (640 / SQRT(2)) = 27.45166004061 or approximately 27 pixels

## See Also

Another interesting constant, The Golden Ratio, φ.

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