For this case, the first thing to do is define a variable.
We have then:
- x: the monetary value of that 120 square foot piece of plastic wrap
We write now the proportion that models the problem.
We have then:
![\frac {23.95} {4500} = \frac {x} {120}](https://img.qammunity.org/2020/formulas/mathematics/middle-school/fmtiv3ylyu61uop6jx1aqbabws89egt92x.png)
From here, we clear the value of x.
We have then:
![x = 120 (\frac {23.95} {4500})](https://img.qammunity.org/2020/formulas/mathematics/middle-school/v7b4o0ieelwk7occ95ijedmc0qxay0fpoi.png)
Calculating we have:
![x = 0<strong>,639</strong>\$](https://img.qammunity.org/2020/formulas/mathematics/middle-school/gbyqhj0hjf1gahnw1q5ixjlrtjwwaceoaw.png)
Answer:
the monetary value of that 120 square foot piece of plastic wrap is:
![x = 0,639\$](https://img.qammunity.org/2020/formulas/mathematics/middle-school/od1m0464qbr9uqvwlcc2uesn9z8ok6i4qj.png)