Menelaus' Theorem, named after King Menelaus of Sparta, as a theory about the collinearity of certain points, which can be figured out by creating a triangle with two sides being intersected by the theoretical line made by the points. if the equation below is satisfied, and the triangles indicated are similar, then the points are collinear. Try moving Point B around and see if anything changes when the points are collinear.
Do the two sets of triangles ever become non-similar? Is the equation ever not balanced? What could you do to cause these things?