We know that the constant of proportionality shows us how much is the change of a variable in relation to the change of another variable.
In this case we want to see how much y changes when x change. In order to find it out we just have to divide them:
[tex]\frac{y}{x}[/tex]We have that the line cross the point (10, 55) from the origin (0, 0). Since (x, y), the change of x is 10 and the change of y is 55. Using the division, we have that:
[tex]\frac{55}{10}=5.5[/tex]is the constant of proportionality of this line.
Answer - A: 5.5
