The correct interpretation of the function notation \( V(3) = 90\pi \) is:
The volume of the cylinder is \( 90\pi \) when the radius is 3.
This correctly reflects the meaning of the function, where \( V(r) \) represents the volume of the cylinder as a function of its radius \( r \). When \( r \) is 3 inches, the volume \( V(3) \) equals \( 90\pi \) cubic inches.