x=2 from cross multiplying.
Option c is correct. Use special right triangles and you will findout why. Hint:Use the 45-45-90 special right triangle's properties.
The area of the circle is
... A = (π/4)d² . . . . where d=10 in
The area of the square is
... A = d² . . . . . . . . where d=10 in
The amount of the square that is not in the circle is
... (1 -π/4)d² = 0.2146018d² ≈ 21.5 in² . . . for d=10 in
You are looking for the shaded region that would be contained in both of the inequalities.
You have:


If you graph an shade the correct half-plane for those equations, you will see there is a triangular region on the left side of the first quadrant.