You need to remember that the product length multiplied by width expresses the area of rectangle.
Considering the the magnitude of vector `barA` expresses the width and the magnitude of vector`barB ` expresses the length and since the problem provides the magnitudes of vectors `barA` and `barB` , then you should use the following property of absolute value such that:
`|bar A|*|bar B| = |barA*barB|`
You need to substitute 2 for `|bar A|` and 5 for `|bar B|` such that:
Area `= |2*5| = |10|` => Area = 10 units`^2`
Hence, evaluating the area of rectangle under given conditions yields A = 10 units`^2` .