a.
This question is a rather odd way to ask you to find the radius of a circle from its area.
A = π r²
40000 = π r²
r² = 40000/π
r = √(40000/π)
r ≈ 112.8379
Answer: 113 miles
b.
C = 2 π r
754 = 2 π r
r = 754/2π = 377/π
A = π r² = A = π (377/π)² = 377²/π
A ≈ 45241.0658
Answer: 45241 square miles
