Final answer:
The dog was able to locate its master by being familiar with the sound of her whistle, indicating a strong bond and training that allowed it to find the source of the sound.
Step-by-step explanation:
To answer the question of how Pi acquires the orange whistle, we can draw a parallel to a scenario where a pet dog uses the sound of its master's whistle to locate her in the woods. Just as the dog was used to his master's whistling and could determine where the sound was coming from, we can infer that Pi acquired the orange whistle from being familiar with its significance and the context within the story. The dog's recognition of the specific sound of the whistle, despite the owner’s change in location, indicates a level of training and a strong bond between the pet and the owner, thus allowing the dog to navigate toward the source of the sound.