Proportion

Definition

Proportion is the relationship between the sizes or quantities of different parts of something. It is a mathematical concept that describes the equality of ratios between corresponding parts of two or more quantities or figures.

5 Must Know Facts For Your Next Test

1. Proportions are used to solve percent applications by setting up an equivalent ratio.
2. Proportions are essential in solving problems involving similar figures, where corresponding sides are proportional.
3. Direct variation is a special type of proportion where two quantities are directly proportional, meaning one increases as the other increases.
4. Inverse variation is the opposite of direct variation, where one quantity decreases as the other increases, maintaining a constant proportion.
5. Proportions are fundamental in understanding and solving a wide range of mathematical problems, from everyday applications to advanced geometry and algebra.

Review Questions

• Explain how proportions are used to solve percent applications.
  • Proportions are used to solve percent applications by setting up an equivalent ratio between the known and unknown quantities. For example, in a problem asking to find the original amount when given the percent and the new amount, a proportion can be set up where the original amount is to the new amount as 100% is to the given percent. This proportion can then be solved to find the original amount.
• Describe the role of proportions in solving problems involving similar figures.
  • Proportions are essential in solving problems involving similar figures, where corresponding sides are proportional. By setting up a proportion between the lengths of corresponding sides, you can determine unknown side lengths or other properties of the similar figures. This is important in applications such as scale drawings, map reading, and solving problems in geometry.
• Analyze the relationship between proportions and direct and inverse variation.
  • Proportions are fundamental to understanding direct and inverse variation. In direct variation, two quantities are directly proportional, meaning they increase or decrease in a constant ratio. This can be represented as a proportion, where the ratio of the two quantities remains the same. Inverse variation, on the other hand, describes a relationship where one quantity decreases as the other increases, but their product remains constant, which can also be expressed as a proportion.

Related terms

Ratio:

The quantitative relationship between two or more quantities, expressed as a fraction or percentage.

Similar Figures:

Geometric shapes that have the same shape but may differ in size, with corresponding sides proportional.

Direct Variation:

A relationship between two variables where one variable increases or decreases in direct proportion to the other.