Answer: The distance between them is 230.65 miles.
Explanation:
Since we have given that
Speed of plane A (b) = 200 miles per hour
Speed of plane B (c) = 300 miles per hour
Angle between them = 50°
So,
We will use the "Cosine formula", we get

So, distance between the two planes after one hour will be

So, the distance between them is 230.65 miles.