Answer:  The magnitude of the vector u is √12 units.
Step-by-step explanation: Â Given that the dot product of a vector u with itself is 12.
We are to find the magnitude of the vector u.
Let <a, b> represents the vector u.
That is, u = <a, b>
Then, according to the given information, we have
Thus, the magnitude of the vector u is √12 units.