(b)
Diameter of the circle = AC
= diagonal of the square = \(\sqrt2x\) cm
∴ Radius of the circle = \(\frac{\sqrt2x}{2}\) cm = \(\frac{x}{\sqrt2}\) cm

Hence, area of the circle = π(\(\frac{x}{\sqrt2}\))2 cm2
= \(\frac{πx^2}{2}\) cm2
Area of the square = x2
∴ Required area = \(\frac{πx^2}{2}\) - x2 = \(\frac{x^2}{2}\) (π - 2) cm2.