Solution:
Given:
[tex]\text{Standard size American flag of 3' x 5'}[/tex]Let L be the longer side of the mega flag.
Another company produces a similar flag of 48' x L
Since both flags are similar, then the ratio of the corresponding sides is equal.
Hence,
[tex]\begin{gathered} \frac{3}{5}=\frac{48}{L} \\ \\ \text{Cross multiplying the equation,} \\ 3\times L=5\times48 \\ 3L=240 \\ \\ \text{Dividing both sides by 3,} \\ L=\frac{240}{3} \\ L=80^{\prime} \end{gathered}[/tex]Therefore, the length of the longer side of the mega flag is 80'