Answer: 6.4 degrees
Explanation:
a= 5 degrees temperature difference to the north gives the opposite of the triangle,
b = 4 degrees temperature difference to the west gives the adjacent,
c = temperature difference of 1 mile to the south east gives the hypotenuse.
Therefore,
Using Pythagoras equation,
c² = b² + a²
c = sqrt( 5² + 4²)
c = sqrt(41) = 6.4 degrees
Therefore, there will be 6.4 degrees temperature difference 1 mile to the south east