3226. While navigating in fog off a coastline of steep cliffs, you hear the echo of the ship's foghorn 4 1/2 seconds after the signal was sounded. What is the distance to the shore?

The echo time of 4.5 seconds represents the round trip of the sound, requiring the total distance to be calculated and then halved to determine the distance to the shore. Using a speed of sound of 1100 ft/sec, the total distance is 4950 ft, which converts to 825 yards.