Find the compound ratio of 2 : 3, 9 : 14 and 14 : 27.

Compound ratio of 2 : 3, 9 : 14 and 14 : 27,

$= \dfrac{2}{3} \times \dfrac{9}{14} \times \dfrac{14}{27} \\[1em] = \dfrac{252}{1134} \\[1em] = \dfrac{2}{9} = 2 : 9.$

Hence, compound ratio of 2 : 3, 9 : 14 and 14 : 27 is 2 : 9.