In a direct variation equation of the form \( y = kx \), the constant of proportionality is the coefficient \( k \).
In the given equation \( y = \frac{2}{2/3}x \), we can simplify \( \frac{2}{2/3} \).
To simplify \( \frac{2}{2/3} \), multiply by the reciprocal of \( \frac{2}{3} \):
\[ \frac{2}{2/3} = 2 \times \frac{3}{2} = 3 \]
Thus, the equation simplifies to:
\[ y = 3x \]
So, the constant of proportionality \( k \) is \( 3 \).