Ответ:

\(y:8.4=\frac{13}{8}:\frac{27}{4}\).

\(\frac{y}{8.4}=\frac{13}{8}\cdot\frac{4}{27}=\frac{13}{54}\).

\(y=8.4\cdot\frac{13}{54}=\frac{91}{45}=2\frac{1}{45}\).

Ответ: \(y=2\frac{1}{45}\).