Answer:
See Explanation
Explanation:
Given two variables (say x and y); the constant of proportionality is the ratio between these to variables.
Illustration; y is directly proportional to x
The above statement can be represented as:

When converted to an equation, you get

k, in the above equation, represents the constant of proportionality
Divide both sides by x to solve for k

Take for instance:

Divide both sides by x
--- 3 is the constant of proportionality