For a triangle ABC and a transversal line meeting BC, CA, AB at X, Y, Z (with points extended if necessary), the product of signed ratios (BX/XC)(CY/YA)(AZ/ZB) = −1; conversely, that identity forces collinearity. Attributed to Menelaus of…
For a triangle ABC and a transversal line meeting BC, CA, AB at X, Y, Z (with points extended if necessary), the product of signed ratios (BX/XC)(CY/YA)(AZ/ZB) = −1; conversely, that identity forces collinearity. Attributed to Menelaus of…