From the given table,
[tex]\begin{gathered} (a)8ft\colon6ft=4\colon3 \\ (b)x\colon24=4\colon12 \\ \frac{x}{24}=\frac{4}{12} \\ x=4\times2 \\ x=8\text{ ft} \\ (c)7ft\colon x=3\colon12 \\ \frac{7}{x}=\frac{3}{12} \\ x=4\times7 \\ x=28\text{ ft} \end{gathered}[/tex]