Area of shaded region = (area of square FGHJ) - (area of sector FGJ)

(area of square FGHJ
Since each side of the square has length x, the area = \(x^2\)

area of sector FGJ
Area of sector = \((\frac{n}{360})(\pi)(radius^2)\), where \(n =\) the central angle

Since FGHJ is a square, we know that the central angle (angle GFJ) \(= 90°\)
We also know that the radius \(= x\)
So, the area of sector FGJ \(= (\frac{90}{360})(\pi)(x^2)= (\frac{1}{4})(\pi)(x^2)=\) \(\frac{\pi x^2}{4}\)

Area of shaded region = \(x^2\) \(-\) \(\frac{\pi x^2}{4}\)

= \(\frac{4x^2}{4}\) \(-\) \(\frac{\pi x^2}{4}\)

= \(\frac{4x^2 - \pi x^2}{4}\)

We get:
Quantity A: \(\frac{4x^2 - \pi x^2}{4}\)

Quantity B: \(\frac{x^2}{4}\)

Multiply both quantities by \(4\) to get:
Quantity A: \(4x^2 - \pi x^2\)
Quantity B: \(x^2\)

Divide book quantities by \(x^2\) to get:
Quantity A: \(4 - \pi \)
Quantity B: \(1\)

In other words we have:
Quantity A: \(4 - 3.14 = 0.86 \)
Quantity B: \(1\)

Answer: B