Key Terms

circumference of a circle

The distance around a circle is called its circumference.

diameter of a circle

A diameter of a circle is a line segment that passes through a circle’s center connecting two points on the circle.

equivalent decimals

Two decimals are equivalent decimals if they convert to equivalent fractions.

mean

The mean of a set of $n$ numbers is the arithmetic average of the numbers. The formula is $\text{mean}=\frac{\text{sum of values in data set}}{n}$

median

The median of a set of data values is the middle value.

• Half the data values are less than or equal to the median.
• Half the data values are greater than or equal to the median.

mode

The mode of a set of numbers is the number with the highest frequency.

radius of a circle

A radius of a circle is a line segment from the center to any point on the circle.

rate

A rate compares two quantities of different units. A rate is usually written as a fraction.

ratio

A ratio compares two numbers or two quantities that are measured with the same unit. The ratio of $a$ to $b$ is written $a$ to $b$, $\frac{a}{b}$, or $a:b$.

repeating decimal

A repeating decimal is a decimal in which the last digit or group of digits repeats endlessly.

unit price

A unit price is a unit rate that gives the price of one item.

unit rate

A unit rate is a rate with denominator of 1 unit.