21. Решить пропорции: 1) x : 4 1/3 = 8 : 17 1/8; 2) 0,37 : 2 5/6 = x : 8,5.

1. \(4\frac13=\frac{13}{3}\), \(17\frac18=\frac{137}{8}\).
   \(\frac{x}{13/3}=\frac{8}{137/8}\).
   \(x=\frac{13}{3}\cdot\frac{64}{137}=\frac{832}{411}\).
2. \(2\frac56=\frac{17}{6}\), \(8.5=\frac{17}{2}\).
   \(\frac{0.37}{17/6}=\frac{x}{17/2}\).
   \(x=0.37\cdot\frac{17}{6}\cdot\frac{2}{17}=\frac{0.37}{3}=\frac{37}{300}\).

Ответ: 1) \(x=\frac{832}{411}\); 2) \(x=\frac{37}{300}\).