We could just solve this using proportions,
[tex]\frac{flagpole\text{ length}}{\text{flagpole shadow length}}=\frac{stick\text{ length}}{\text{stick shadow length}}[/tex]Thus, we have
[tex]\begin{gathered} \frac{x}{28}=\frac{2}{3.5} \\ \text{cross multiply} \\ 3.5x=56 \\ \text{divide both sides by 3.5} \\ x=16ft \end{gathered}[/tex]The flagpole is 16ft long.
