We have the following, L, of the beam varies as the product of the width and the square of the height:
[tex]L\propto w\cdot h^2[/tex]And varies inversely as the lenght of the wooden beam:
[tex]L\propto\frac{w\cdot h^2}{l}[/tex]therefore:
[tex]L=k\cdot\frac{w\cdot h^2}{l}[/tex]where k is the proportionality constant
w = 4, h=8, l = 216 and L = 5050
[tex]\begin{gathered} 5050=k\cdot\frac{4\cdot8^2}{216} \\ k=\frac{5050\cdot216}{256} \\ k=4260.93 \end{gathered}[/tex]now, if w = 2, h = 5, l = 144:
[tex]\begin{gathered} L=4260.93\cdot\frac{2\cdot5^2}{144} \\ L=1479.5 \end{gathered}[/tex]