Final answer:
The shortest distance between point A and point X is 5.0 km.
Step-by-step explanation:
To find the shortest distance between point A and point X, we can use the Pythagorean theorem. Since the man walks 3.0 km northeast and then 4.0 km southeast, we can consider these paths as two sides of a right triangle. The distance between A and X is the hypotenuse of this triangle.
Let's assume that the distance between A and X is 'd'. We can apply the Pythagorean theorem to find 'd':
d^2 = (3.0 km)^2 + (4.0 km)^2
d^2 = 9.0 km^2 + 16.0 km^2
d^2 = 25.0 km^2
d = 5.0 km
So, the shortest distance between point A and point X is 5.0 km.