Proportions

In mathematics, the word "proportions" means two ratios put into an equation.^[1] Some examples of proportions are:

• ⁵⁰⁄₁₀₀ = ¹⁄₂
• ⁷⁵⁄₁₀₀ = ³⁄₄
• +^x⁄₁₀₀ = ³⁄₄, where x = 75.

In algebra, proportions can be used to solve many common problems about changing numbers. As an example, for the increase in a $40 purchase of gasoline (petrol), if the price rose 35 cents, from $3.50 to $3.85, then the proportion would be:

• +^x⁄_3.85 = +^$40⁄_3.50

The solution is simply:

• x = $40/3.50 x 3.85   =   $44.00, or $4 more when $0.35 higher.

Many other common calculations can be solved by using proportions to show the relationships between the numbers.

In statistics, a proportion is a number which measures the extent to which a specific characteristic is in a sample or a population. It can be thought of as a percentage. To represent a sample proportion, the letters ${\displaystyle p}$ can be used. To represent a population proportion, the letter ${\displaystyle \pi }$ can be used.^[2]

1. ↑ "Proportion". www.learnalberta.ca. Retrieved 2020-10-07.
2. ↑ "Greek/Hebrew/Latin-based Symbols in Mathematics". Math Vault. 2020-03-20. Retrieved 2020-10-07.