Question

Assessment items Item 13 The variables x and y vary directly. Use the values to find the constant of proportionality, k. Then write an equation that relates x and y . y=72; x=3 k= y=

Answer 1

to find the constant of proportionality you gotta divide the x by the y to get your answer 

Answer 2

A proportion can be written as
y = kx
Substituting the given information, we can find k.
72 = k*3
72/3 = k = 24

You have ...
k = 24
y = 24x