When a particular wire is bent into the shape of a square, then the area of the square turns out to be $81\,cm^2$. When the same wire is bent into a circle, then the radius of the circle (correct to two decimal places) is

5.73

The correct answer is Option (2) → 5.73

Area of the square = 81 cm²

So, side of the square = $\sqrt{81} = 9$ cm

Perimeter of the square (length of the wire)
= 4 × 9 = 36 cm

When bent into a circle:
Circumference = $2πr = 36$

So,

$r = \frac{36}{2\pi} = \frac{18}{\pi} \approx 5.73 \text{ cm}$