найти неизвестный член пропорции 1целая2/8:8целых 1/3=х:4/9

х = ( 10/8 * 4/9) : 25/3 х = 5/9 : 25/3 х = 5/9 * 3/25 х=1/10

решение*

(1 2/8)/(8 1/3) = x/(4/9)1 2/8 * 4/9 = 8 1/3 * x40/72 = 25/3 * x(40/72)/(25/3) = x(40*3)/(72*25) = x120/1800 = xx = 1/15