here's the hint:
diagonals of a rectangle are ... ?
A surveyor starts at the center of a circular park with radius 7 miles.
He walks 3 miles directly east and drives a stake into the ground at point
He walk directly north until he reaches the perimeter of the park.
Then he walks directly west until he is directly north of the center,
. . and drives a stake into the ground at point
Find the distance
[The shortest solution, please.]