Answer:
[tex] \frac{4}{7} [/tex]
Step-by-step explanation:
The constant of proportionality is the slope of the line joining the two points
(70,40) and (49,28).
Recall the slope formula:
[tex]m = \frac{ y_2 - y_1 }{ x_2 - x_1} [/tex]
We substitute the point to get:
[tex]m = \frac{28 - 40}{49 - 70} = \frac{ - 12}{ - 21} = \frac{4}{7} [/tex]
Alternatively:
A proportional relation is given by
[tex]y = kx[/tex]
where k is the constant of proportionality.
Using any point, we substitute and solve for k.
[tex]40 = 70k[/tex]
[tex]k = \frac{40}{70} = \frac{4}{7} [/tex]
