To compute the width of the wing, we can use the next proportion
[tex]\frac{9\text{ meters long}}{43.9\text{ meters long}}=\frac{1\text{ meter wide}}{x\text{ meters wide}}[/tex]Solving for x,
[tex]\begin{gathered} 9\cdot x=1\cdot43.9 \\ x=\frac{43.9}{9} \\ x=4.88 \end{gathered}[/tex]The airplane wing must be 4.88 meters wide.
