The Pythagorean theorem tells you the distance between the locations is
√(52² +75²) ≈ 91.23 mi
The appropriate choice is
B. 91 mi
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An approximation that can get you within 6% of the correct value is this: add 1/3 of the short side of the right triangle to the long side. Here, that is
75 + 52/3 = 92.3
This is close enough to the correct value to let you choose the correct answer.