A table of values can be used to represent variables that are directly proportional.
The complete table of proportions is:
![\left[\begin{array}{ccccccccc}Letters&10&2&[150 ]&7&1&500&[420] \\Cost&0.45&0.90&6.75&[0.315]&[0.045 ]&[22.5 ] & 18.90\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccccccccc%7DLetters%2610%262%26%5B150%20%5D%267%261%26500%26%5B420%5D%20%5C%5CCost%260.45%260.90%266.75%26%5B0.315%5D%26%5B0.045%20%5D%26%5B22.5%20%5D%20%26%2018.90%5Cend%7Barray%7D%5Cright%5D)
Given that
![\left[\begin{array}{ccccccccc}Letters&10&2&[\ ]&7&1&500&[\ ] \\Cost&0.45&0.90&6.75&[\ ]&[\ ]&[\ ] & 18.90\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccccccccc%7DLetters%2610%262%26%5B%5C%20%5D%267%261%26500%26%5B%5C%20%5D%20%5C%5CCost%260.45%260.90%266.75%26%5B%5C%20%5D%26%5B%5C%20%5D%26%5B%5C%20%5D%20%26%2018.90%5Cend%7Barray%7D%5Cright%5D)
Let:
<em />
<em> Letters</em>
<em />
<em> Cost</em>
<em />
Using proportional reasoning, we have:
![C = kL](https://tex.z-dn.net/?f=C%20%20%3D%20kL)
Where
<em />
<em> ratio of proportion</em>
For the first values of C and L, we have:
![C = kL](https://tex.z-dn.net/?f=C%20%20%3D%20kL)
![0.45 = k \times 10](https://tex.z-dn.net/?f=0.45%20%3D%20k%20%5Ctimes%2010)
Divide both sides by 10
![k = 0.045](https://tex.z-dn.net/?f=k%20%3D%200.045)
So, the equation of proportion is:
![C = 0.045L](https://tex.z-dn.net/?f=C%20%3D%200.045L)
<u>When C = 6.75, we have:</u>
![C = 0.045L](https://tex.z-dn.net/?f=C%20%3D%200.045L)
![6.75 = 0.045L](https://tex.z-dn.net/?f=6.75%20%3D%200.045L)
Solve for L
![L = \frac{6.75}{0.045}](https://tex.z-dn.net/?f=L%20%3D%20%5Cfrac%7B6.75%7D%7B0.045%7D)
![L = 150](https://tex.z-dn.net/?f=L%20%3D%20150)
<u>When L = 7, we have:</u>
![C = 0.045L](https://tex.z-dn.net/?f=C%20%3D%200.045L)
![C = 0.045 \times 7](https://tex.z-dn.net/?f=C%20%3D%200.045%20%5Ctimes%207)
![C = 0.315](https://tex.z-dn.net/?f=C%20%3D%200.315)
<u>When L = 1, we have:</u>
![C = 0.045L](https://tex.z-dn.net/?f=C%20%3D%200.045L)
![C = 0.045 \times 1](https://tex.z-dn.net/?f=C%20%3D%200.045%20%5Ctimes%201)
![C = 0.045](https://tex.z-dn.net/?f=C%20%3D%200.045)
<u>When L = 500, we have:</u>
![C =0.045L\\](https://tex.z-dn.net/?f=C%20%3D0.045L%5C%5C)
![C =0.045 \times 500](https://tex.z-dn.net/?f=C%20%3D0.045%20%5Ctimes%20500)
![C =22.5](https://tex.z-dn.net/?f=C%20%3D22.5)
<u>When C = 18.90, we have:</u>
![C = 0.045L](https://tex.z-dn.net/?f=C%20%3D%200.045L)
![18.90 = 0.045L](https://tex.z-dn.net/?f=18.90%20%3D%200.045L)
Solve for L
![L=\frac{18.90}{0.045}](https://tex.z-dn.net/?f=L%3D%5Cfrac%7B18.90%7D%7B0.045%7D)
![L=420](https://tex.z-dn.net/?f=L%3D420)
Hence, the complete table is:
![\left[\begin{array}{ccccccccc}Letters&10&2&[150 ]&7&1&500&[420] \\Cost&0.45&0.90&6.75&[0.315]&[0.045 ]&[22.5 ] & 18.90\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccccccccc%7DLetters%2610%262%26%5B150%20%5D%267%261%26500%26%5B420%5D%20%5C%5CCost%260.45%260.90%266.75%26%5B0.315%5D%26%5B0.045%20%5D%26%5B22.5%20%5D%20%26%2018.90%5Cend%7Barray%7D%5Cright%5D)
Read more about proportions at:
brainly.com/question/21126582