$$\frac{12}{100} \cdot \frac{25}{4} = \frac{12 \cdot 25}{100 \cdot 4} = \frac{300}{400} $$.
Сократим дробь на 100.
$$\frac{300}{400} = \frac{300:100}{400:100} = \frac{3}{4} $$.
Ответ: $$\frac{3}{4}$$