0.86 : \frac{43}{20} = \frac{86}{100} : \frac{43}{20} = \frac{86}{100} \cdot \frac{20}{43} = \frac{2 \cdot 43}{5 \cdot 20} \cdot \frac{20}{43} = \frac{2}{5} = 0.4
Ответ: 0.4