We have:

The area of the circle is: \(2,5^2\Pi\approx19,63\left(cm^2\right)\)

The diameter of the circle is 2,5 x 2 = 5 cm

=> The side of the square is also 5 cm

So the area of the square is 5 x 5 = 25\(\left(cm^2\right)\)

So the stripe's area is: 25 - 19,63 \(\approx5,38\left(cm^2\right)\)