# 11/9: Group A: Trees;

Group B:Theorems by Cheva and Menelaus

Group A: We will solve a series of problems which can be easily attacked using trees, even if trees are not mentioned in the formulation of the problem.

Group B: Students will first present solutions of problems on barycentric coordinates.
Then, after reviewing the definition of the center of mass via vectors, we will prove (and apply) the theorems by Cheva and Menelaus.