Answer:
[tex]\frac{2}{9}[/tex]
Step-by-step explanation:
Constant of proportionality is defined as the ratio between two directly proportional quantities.
If suppose [tex]x[/tex] and [tex]y[/tex] are the two directly proportional quantities, then we can say that constant of proportionality is given as [tex] \frac{y}{x}[/tex].
Here in the question,
[tex]y=\frac{2}{9}x[/tex]
Dividing both sides by [tex]x[/tex], we get
[tex]\frac{y}{x}=\frac{2x}{9x}[/tex]
[tex]\frac{y}{x}=\frac{2}{9}[/tex]
So, constant of proportionality is [tex]\frac{2}{9}[/tex].