Question 124
On the sides $[AB]$ and $[BC]$ of the parallelogram $ABCD$ one draws the equilateral triangles $ABE$ and $BCF$, so that the points $D$ and $E$ are on the same side of the line $AB$, and points $F$ and $D$ are on different sides of the line $BC$. If $E$, $D$ and $F$ are collinear points, prove that $ABCD$ is a rhombus.