Assume the perimeter of square and equilateral triangle be \(12x\ cm\)
The side of square = \(\frac{12x}{4}\) = \(3x\)
Side of Triangle = \(4x\)
Diagonal of a square = \(d = \sqrt{2} × side\)
= \(3x × \sqrt{2} = 12\sqrt{2}\)
\(x = \frac{12}{3} = 4\)
Sides of Triangle = 4 × 4 = 16 cm
Area of equilateral triangle = \(\frac{\sqrt{3}}{4} cm^2\)
= \(\frac{\sqrt{3}}{4} × (16) × (16)\)
= \(64\sqrt{3} cm^2\)
The correct option is (C): 64√3 cm2