What is the k, the constant of proportionality for this question​

Answer:
k = 0.90
Step-by-step explanation:
y = 18 ; x = 20 ; k = ?
y = k * x
18 = k * 20
k = 18/20
k = 9/10
k = .90
The constant of proportionality basically states that there is a value that will multiply the value of x and make the mathematical statement valid. Hope this helps!