Answer:
A. [tex]y=\frac{1}{4}x[/tex]
Step-by-step explanation:
The Direct Proportionality equation is: f (x) = k.x, where k is the proportionality constant and f (x) is y.
So y = k.x is the mathematical formula or model.
The graphical representation of the direct proportionality function is a line that passes through the origin of coordinates.
In the given case, we must calculate the value of k and then replace it in the formula, being
y = 3
x = 12
k =?
If y = k.x, isolating k is obtained
[tex]k=\frac{y}{x}[/tex]
[tex]k=\frac{3}{12}[/tex]
Expressing the fraction in its simplest form, we have
[tex]k=\frac{3/3}{12/3}[/tex]
[tex]k=\frac{1}{4}[/tex]
Substituting that value in the original formula y = k.x, we have
[tex]y=\frac{1}{4}x[/tex]
Hope this helps!
