Question 1023761
1:8::4:_?      
<pre>
[Note that the word "fraction"
contains the word "ratio"]

{{{fRAcTIOn}}} 

Change the ratios to fractions, 
and the :: to an equal sign:

{{{1/8 = 4/x}}}

Cross-multiply:

{{{1*x =4*8}}}

{{{x=32}}}

----------------

6:2::8:_?

{{{6/2 = 8/x}}}

{{{6*x =8*2}}}

{{{6x=16}}}

{{{x=16/6}}}

{{{x=8/3}}}

Edwin</pre>