Answer:
Constant of variation: the value of k in a direct variation, y = kx
K is the constant which says how y varies with x.
Direct Variation: A function of the form y = kx, where k is not zero.
Here the relation between y and x is a direct variation.
Rate of change : how the dependent variable changes with respect to the independent variable.
In this case, the rate is that k times x is equal to y.