Answer:
W = 9 inches.
Step-by-step explanation:
The volume of a rectangular prism is given by
[tex]V=whl[/tex]
Where
w,h and l re width, height and length of rectangular prism
It is not mentioned that a box has a length of 18 inches and a height of 3 inches.
Using above formula.
[tex]486=w\times 18\times 3\\\\486=54w\\\\w=9\ \text{inches}[/tex]
So, the width of the box is 9 inches.