Answer:
5 miles
Explanation:
The two legs of Deborah's hike form the right-angle legs of a right triangle. The shortest distance is then the hypotenuse of that triangle, found using the Pythagorean theorem.
d^2 = 3^2 + 4^2 = 9 +16 = 25
d = √25 = 5
Deborah ends 5 miles from her start.