(b) 2 : 1
Let each edge of square ABCD = x units
Then, area of square ABCD = x2
For square EFGH, diag. HF = x

⇒ Side of square EFGH = \(\frac{x}{\sqrt2}\)
∴ Area of square EFGH = (\(\frac{x}{\sqrt2}\))2 = \(\frac{x^2}{2}\)
∴ Required ratio = x2 : \(\frac{x^2}{2}\) = 2 : 1.