Question
In $\triangle ABC, D$ and $E$ are two points on the side $AB$ such that $AD = DE = EB$. Through $D$ and $E,$ lines are drawn parallel to $BC$ which meet the side $AC$ at points $F$ and $G$ respectively. Through $F$ and $G$, lines are drawn parallel to $AB$ which meet the side $BC$ at points $M$ and $N$ respectively.Prove that $BM = MN = NC.$


