A ratio is a quantitative relationship between two numbers that describes how many times one value can contain another. Applications of ratios are fairly ubiquitous, and the concept of ratios is quite intuitive.
Value1 : Value2 = Value3 : Value4 OR Value1/Value2=Value3/Value4
For Example 2 : 3= 4 : X then What is X=? Ans. 2/3=4/X X=6