Answer:
8 feet.
Explanation:
We have been given that the volume of this rectangular prism is 108 cubic feet. Width are height are 4.5 feet and 3 feet. We are asked to find the length of the prism.
We know that volume of rectangular prism is product of length, height and width of prism.
![V=lwh](https://img.qammunity.org/2020/formulas/mathematics/middle-school/bvp4fjgrccm3abk4rodt64aizld4dy78uj.png)
Upon substituting our given values in volume formula, we will get:
![108\text{ ft}^3=l(4.5\text{ ft})(3\text{ ft})](https://img.qammunity.org/2020/formulas/mathematics/middle-school/fwrs184qihsqx0c0rncccnqw38no8b0z4z.png)
![108\text{ ft}^3=l(13.5\text{ ft}^2)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/7u3e25y8zjkl1o291n2n9sopsjxhkh8rw7.png)
![l(13.5\text{ ft}^2)=108\text{ ft}^3](https://img.qammunity.org/2020/formulas/mathematics/middle-school/me2aqvn31nv39qu3fbv8jkavcljyjs2gc9.png)
![\frac{l(13.5\text{ ft}^2)}{13.5\text{ ft}^2}=\frac{108\text{ ft}^3}{13.5\text{ ft}^2}](https://img.qammunity.org/2020/formulas/mathematics/middle-school/jhcvu94f5lgnh4eyjl9uh68lmk3xdjuyht.png)
![l=8\text{ ft}](https://img.qammunity.org/2020/formulas/mathematics/middle-school/zaol6hxu6rdevyjc7ctlx57v3fcgsq1gs6.png)
Therefore, the length d the prism is 8 feet.