A proportional relationship is represented by the equation 2x=18y. If y=kx, where k is the constant of proportionality, what is the value of k?
Answers could possibly be 1/9, 1/2, 2, 9 (multiple choice)
18y = 2x divide both sides by 18
y = (2/18) x
y = (1/9) x
So k = 1/9
In these problems, I always try to match it to the form y=kx.
You can do this by isolating k