[tex]\begin{gathered} T=\text{ 2}\pi\sqrt[\placeholder{⬚}]{\frac{L}{9.8}} \\ 4.5=\text{ 2}\pi\sqrt[\placeholder{⬚}]{\frac{L}{9.8}} \\ \frac{4.5}{2\pi}=\text{ }\sqrt[]{\frac{L}{9.8}} \\ 0.7162=\text{ }\sqrt[]{\frac{L}{9.8}} \\ (0.7162)^2=\frac{L}{9.8} \\ 0.513(9.8)=L \\ 5.027=L \\ L\approx5.0m \end{gathered}[/tex]
Approximately 5 meters long.
