Ratios and Proportions

Ratio

The ratio of one quantity to an other is a fraction - and the number of times one quantity is contained in another quantity of the same kind.

The ratio between two quantities is the quotient obtained by dividing the first quantity by the second.

Example - Ratio

The ratio between 3 and 6 can be expressed as

3 / 6 = 1 / 2 = 0.5

Ratio can also be indicated by the sign ":" - like 3 : 6 or 1 : 2 .

Reciprocal or Inverse Ratio

The reciprocal or inverse ratio is the opposite of the original ratio.

Example the Inverse Ratio

The inverse ratio between 6 and 3 can be expressed as

6 : 3  = 2 : 1 = 2

Proportion

Proportion is the equality of ratios.

Example - Proportion

1 : 2 = 3 : 6

or

1 : 2 :: 3 : 6