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
Related Topics
• Basics
Basic engineering data. SI-system, unit converters, physical constants, drawing scales and more.
• Mathematics
Mathematical rules and laws - numbers, areas, volumes, exponents, trigonometric functions and more.
Related Documents
Energy Balance and Energy Ratio
Energy balance and energy payback ratio.
Fractions
Law of fractions
Movement Ratio
Machines and movement ratio (velocity ratio).
Percentage
Working with relative values.
Poisson's Ratio
When a material is stretched in one direction it tends to get thinner in the other two directions.
Poisson's Ratios Metals
Some metals and their Poisson's Ratios.