cross ratio
nounGeometry.
a ratio relating four points in the real or complex plane.
Origin of cross ratio
1First recorded in 1880–85
- Also called anharmonic ratio .
Other words from cross ratio
- cross-ra·ti·o, adjective
Words Nearby cross ratio
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024
How to use cross ratio in a sentence
Before we draw conclusions from this result, we must investigate the meaning of a cross-ratio somewhat more fully.
If we take the points in a different order, the value of the cross-ratio will change.
It is convenient to let the point at infinity occupy the last place in the symbolic expression for the cross-ratio.
The cross-ratio of any four points in one equals that of the corresponding points in the other.
In other words, four lines in a flat pencil are cut by every other line in four points whose cross-ratio is constant.
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