Answer:
k = [tex]\frac{2}{3}[/tex]
Step-by-step explanation:
Given that y is proportional to x then the equation relating them is
y = kx ← k is the constant of proportionality
y = [tex]\frac{2}{3}[/tex] x ← is in this form
with k = [tex]\frac{2}{3}[/tex]