Chapter 1: Ratios & Proportional Reasoning

constant of proportionality

A constant ratio or unit rate of two variable quantities. It is also called the constant of variation.

complex fraction

A fraction with a numerator, denominator, or both that are also fractions.

ordered pair

a pair of numbers used to locate a point in the coordinate plane. This is written in the form (x-coordinate, y-coordinate)

coordinate plane

a plane in which a horizontal number line and a vertical number line intersect at their zero points. Also called a coordinate grid.

rate of change

a rate that describes how one quantity changes in relation to another. A rate of change is usually expressed as a unit rate.

unit rate

a rate that is simplified so that it has a denominator of 1 unit.

rate

a ratio that compares two quantities with different kinds of units.

quadrants

one of the four regions into which the two perpendicular number lines of the coordinate plane separate the plane.

constant of variation

the constant ratio in a direct variation. It is also called the constant of proportionality.

x-coordinate

the first number of an ordered pair. It corresponds to a number on the x-axis.

x-axis

the horizontal number line in a coordinate plane.

constant rate of change

The rate of change in a linear relationship.

unit ratio

a unit rate where the denominator is one unit.

proportion

an equation stating that two ratios or rates are equivalent.

origin

the point at which the x-axis and y-axis intersect in a coordinate plane.

dimensional analysis

the process of including units of measurement when you compute.

cross products

the products of the numerator of one ratio and the denominator of the other ratio.

slope

the rate of change between any two points on a line. It is the vertical change to the horizontal change. It tells how steep the line is.

proportional

the relationship between two ratios or rates are equivalent.

nonproportional

the relationship between two ratios with a rate or ratio that is not constant.

direct variation

the relationship between two variable quantities that have a constant ratio.

y-coordinate

the second number of an ordered pair. It corresponds to a number on the y-axis.

y-axis

the vertical number line in a coordinate plane.

equivalent ratios

two ratios that have the same value.