The area of a regular hexagon of side 2√3 cm is:

A regular hexagon consists of 6 equilateral triangle
Area of regular hexagon
$$\eqalign{ & = 6 \times \frac{{\sqrt 3 }}{4} \times {\left( {{\text{side}}} \right)^3} \cr & = 6 \times \frac{{\sqrt 3 }}{4} \times {a^2} \cr & = 6 \times \frac{{\sqrt 3 }}{4} \times {\left( {2\sqrt 3 } \right)^2} \cr & = 6 \times \frac{{\sqrt 3 }}{4} \times 12 \cr & = 18\sqrt 3 {\text{ c}}{{\text{m}}^2} \cr} $$