ANSWER:
492 gallons
Explanation:
Given:
length: 8 ft
width: 4 ft
height: 2 ft
The first thing is to calculate the volume of the waterbed, since it is a rectangular prism, the volume is the product of its length, width and height.
![\begin{gathered} V=8\cdot4\cdot2 \\ V=64ft^3 \end{gathered}](https://img.qammunity.org/2023/formulas/physics/college/1nuukbls8dpj98psteim9ony806rgxfqib.png)
Knowing the volume in cubic feet, we can convert this value to gallons thanks to the conversion factor, where 1 gallon is equal to 0.13 cubic feet.
We perform the operation, just like this:
![\begin{gathered} 64ft^3\cdot\frac{1\text{ gal}}{0.13ft^3}=492.30\text{ gal} \\ 492.30\text{ gal }\cong492\text{ gal} \end{gathered}](https://img.qammunity.org/2023/formulas/physics/college/wbdodx3kk2zdhxbxk84cz69j0ycruvaue5.png)
Therefore a total of 492 gallons are needed.