To solve the proportion \(\frac{x}{5} = \frac{8}{9}\), you can cross-multiply:
\[ x \cdot 9 = 8 \cdot 5 \]
This simplifies to:
\[ 9x = 40 \]
Next, divide both sides by 9 to isolate \(x\):
\[ x = \frac{40}{9} \]
So, the solution is:
\[ x = \frac{40}{9} \]