б) 12:29 = \(\frac{1}{58}\): x;
Преобразуем пропорцию:
\(\frac{12}{29} = \frac{\frac{1}{58}}{x}\)
\(12 \cdot x = \frac{1}{58} \cdot 29\)
\(12x = \frac{1}{2}\)
\(x = \frac{1}{2} : 12 = \frac{1}{2} \cdot \frac{1}{12} = \frac{1}{24}\)
Ответ: \(x = \frac{1}{24}\)