Geometry: Hexagon Area from Equilateral Triangles

The sides of $\triangle ABC$ are trisected by the intersecting equilateral triangle $\triangle XYZ$. Thus each side of the hexagon MNOPQRM is $54 / 3 = 18$ cm. The area of a regular hexagon of side $s = 18$ cm is: $\text{Area} = \frac{3\sqrt{3}}{2} \cdot s^2 = \frac{3\sqrt{3}}{2} \cdot 18^2 = \frac{3\sqrt{3}}{2} \cdot 324 = 486\sqrt{3} \text{ sq. cm.}$