Question

14:15=3:x пропорцией

Answer 1

$\frac{14}{15} = \frac{3}{x} \\ x = \frac{3 \times 15}{14} = \frac{45}{14} = 3.2142857143$

Answer 2

14:15=3:x
14*x = 15*3
14x = 45
x = 45:14
x = 3 3/14