493.m:$$\frac{25}{6}=\frac{4}{7}:\frac{20}{21}$$

m:$$\frac{25}{6}=\frac{4}{7}:\frac{20}{21}$$

m:$$\frac{25}{6}=\frac{4}{7}\cdot \frac{21}{20}$$

m:$$\frac{25}{6}=\frac{3}{5}$$

$$m=\frac{3}{5}\cdot \frac{25}{6}$$

$$m=\frac{5}{2}$$

$$m=2\frac{1}{2}$$

Ответ: $$2\frac{1}{2}$$