# CrossRatio Command

From GeoGebra Manual

- CrossRatio( <Point A>, <Point B>, <Point C>, <Point D> )
- Calculates the cross ratio
*λ*of four collinear points*A*,*B*,*C*and*D*, where:*λ = AffineRatio[B, C, D] / AffineRatio[A, C, D].* **Example:**`CrossRatio((-1, 1), (1, 1), (3, 1), (4, 1))`

yields*1.2*