Final answer:
To find the rate at which the distance between two planes is decreasing, we need to use the concept of relative velocity and the Pythagorean theorem.
Step-by-step explanation:
To find the rate at which the distance between the planes is decreasing, we need to use the concept of relative velocity. We can consider Plane A as the reference point and calculate the velocity of Plane B with respect to A. When Plane A is 2 nautical miles from the intersection point, the distance between Plane A and the intersection point is 2 nautical miles. Similarly, when Plane B is 6 nautical miles from the intersection point, the distance between Plane B and the intersection point is 6 nautical miles. Using the Pythagorean theorem, we can calculate the distance between the two planes. Then, by differentiating this distance with respect to time, we can find the rate at which the distance is decreasing.