RRB Group-D Model Paper 13 with answers for online practice

Let the diagonal be x
Side of square = $\frac{\mathit{x}}{\sqrt{2}}$
Then, area of square from diagonal = $\mathit{s}\mathit{i}\mathit{d}{\mathit{e}}^2=\frac{{\mathit{x}}^2}{2}$
$\frac{{\mathit{x}}^2}{2}=6\sqrt{3}$
On solving we get,
${\mathit{x}}^2=12\sqrt{3}$
Area of an equilateral triangle with sides equal to the diagonal of the square i.e. x
Area = $\frac{\left(\sqrt{3}{\mathit{x}}^2\right)}{4}$
Area = (12 × 3)/4
Area = 9 sq. cm