The Problem Suppose ABC is any triangle. D, E, F are points on BC, CA, AB respectively such that $latex (\frac{BD}{DC} = \frac{CE}{EA} = \frac{AF}{FB})$. Prove that the centroids of triangles ABC and DEF coincide. A little Complex Number Let A, B, C be points on the Complex plane with complex coordinates a, b, c. […]