Answer:
The side of the square is 5.971 cm
Step-by-step explanation:
If the square fits the circle exactly, then its diagonal is equal to the diameter of the circle. Since the side of the square has a length of
cm, then it's diagonal have the length of
cm. Using the circle's area we can find the diagonal of the square, as shown below:

Since the diameter of the circle is the same as the diagonal of the square, then:

The side of the square is 5.971 cm