Lill's Method for Calculating the Value of a Cubic Polynomial
This Demonstration shows Lill's graphic method for calculating the value of a cubic polynomial using the Horner formulas:[more]
This is true by Thales's side-splitter theorem. For instance , .[less]
This method is attributed to the French engineer Eduard Lill (1867).
The side-splitter theorem states: If a line parallel to one side of a triangle intersects the other two sides in different points, it divides the sides in the same ratio [2. p. 354].
 D. Kurepa, Higher Algebra (in Croatian), Zagreb: Skolska knjiga, 1965 pp. 1071–1073.
 H. R. Jacobs, Geometry (2nd ed.), New York: W. H. Freeman and Company, 1987.