29. Реши пропорцию.

Решение:

1. \( \frac{1}{5} = \frac{4}{x} \)
\( x = 5 \cdot 4 = 20 \)
2. \( \frac{2}{x} = \frac{6}{7} \)
\( 6x = 2 \cdot 7 = 14 \)
\( x = \frac{14}{6} = \frac{7}{3} \)
3. \( \frac{8}{x} = \frac{8}{27} \)
\( 8x = 8 \cdot 27 \)
\( x = 27 \)
4. \( \frac{10}{4} = \frac{4}{x} \)
\( 10x = 4 \cdot 4 = 16 \)
\( x = \frac{16}{10} = \frac{8}{5} \)

Ответ: 1. 20; 2. 7/3; 3. 27; 4. 8/5.