- a) $$\frac{x}{10} = \frac{1}{5}; \; x = \frac{10 \cdot 1}{5} = 2$$
- б) $$\frac{5}{12} = \frac{x}{24}; \; x = \frac{5 \cdot 24}{12} = 10$$
- в) $$\frac{2}{8} = \frac{x}{4}; \; x = \frac{2 \cdot 4}{8} = 1$$
- г) $$\frac{18}{27} = \frac{x}{3}; \; x = \frac{18 \cdot 3}{27} = 2$$
Ответ: a) 2; б) 10; в) 1; г) 2.