Similarity ratio from A to B = \(\displaystyle{\frac{{{3}}}{{{8}}}}\)

similarity ratio = \(\frac{side\ length\ of\ first\ triangle}{corresponding\ side\ of\ second\ triangle}\)

given similarity ratio = \(\displaystyle{\frac{{{3}}}{{{8}}}}={\frac{{{x}}}{{{24}}}}\)

\(\displaystyle{x}={\frac{{{3}\times{24}}}{{{8}}}}\)

x=9