Final answer:
The magnitude of the cross product cannot be determined without the angle between the vectors.
Step-by-step explanation:
The cross product of two vectors A and B, denoted as A x B, is a vector that is perpendicular to both vectors. The magnitude of the cross product can be calculated using the formula |A x B| = |A| |B| sin(θ), where |A| and |B| are the magnitudes of the vectors and θ is the angle between them.
In this case, the magnitude of vector a is 5 and the magnitude of vector b is 9. Since the angle between the two vectors is not provided, we cannot determine the magnitude of the cross product without that information.