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

(1 2/8)/(8 1/3) = x/(4/9)
1 2/8 * 4/9 = 8 1/3 * x
40/72 = 25/3 * x
(40/72)/(25/3) = x
(40*3)/(72*25) = x
120/1800 = x
x = 1/15