Help please Idk how to answer

Julia is going for a walk through the neighborhood. what unit of measure is most appropriate to describe the distance she walks?

If you answer right ill give brainliest, : )

If the ratio of sum of the first m and n terms of an ap is m2 : n2 , show that the ratio of its mth and nth terms is (2m − 1) : (2n − 1).