If 2 : 3 :: 6 : x are in proportion, then x = 

The correct option is C 9
Given, 2 : 3 :: 6 : x 
We can write the above proportion as 
$\frac{2}{3}=\frac{6}{x}$
On cross multiplying,
$x=\frac{18}{2}$ 
$\therefore$ x = 9

Mathematics