absolute value

The distance of a number from zero; the positive value of a number.

acute angle

A positive angle measuring less than 90 degrees.

acute triangle

A triangle each of whose angles measures less than 90 degrees.

additive identity

additive inverse

adjacent angles 

 
Two angles that share both a side and a vertex.

angle 

 
The union of two rays with a common endpoint, called the vertex.

arc
 

 
A portion of the circumference of a circle.

area
 

 
The number of square units that covers a shape or figure.

associative property of addition
 

 
(a + b) + c = a + (b + c)

associative property of multiplication
 

 
(a x b) x c = a x (b x c)

average
 

 
A number that represents the characteristics of a data set.

axis of symmetry 

 
A line that passes through a figure in such a way that the part of the figure on one side of the line is a mirror reflection of the part on the other side of the line.

base
 

 
The bottom of a plane figure or three-dimensional figure.

Bisect
 

 
To divide into two congruent parts.

Box and whisker plot 

 
A type of data plot that displays the quartiles and range of a data set.

Cartesian coordinates
 

 
A system in which points on a plane are identified by an ordered pair of numbers, representing the distances to two or three perpendicular axes.

central angle
 

 
An angle that has its vertex at the center of a circle.

chord
 

 
A line segment that connects two points on a curve.

circle
 

 
The set of points in a plane that are a fixed distance from a given point, called the center.

circumference
 

 
The distance around a circle.

coefficient
 

 
A constant that multiplies a variable.

collinear
 

 
Points are collinear if they lie on the same line.

combination
 

 
A selection in which order is not important.

common factor
 

 
A factor of two or more numbers.

common multiple
 

 
A multiple of two or more numbers.

commutative property of addition
 

 
a + b = b + a.

commutative property of multiplication 

 
a*b = b*a.

complementary angles
 

Two angles whose sum is 90 degrees.

composite number
 

 
A natural number that is not prime.

cone
 

 
A three-dimensional figure with one vertex and a circular base.

congruent 

 
Figures or angles that have the same size and shape.

constant
 

 
A value that does not change.

coordinate plane
 

 
The plane determined by a horizontal number line, called the x-axis, and a vertical number line, called the y-axis, intersecting at a point called the origin. Each point in the coordinate plane can be specified by an ordered pair of numbers.

coplanar
 

 
Points that lie within the same plane.

counting numbers
 

 
The natural numbers, or the numbers used to count.

counting principle
 

 
If a first event has n outcomes and a second event has m outcomes, then the first event followed by the second event has n times m outcomes.

cross product
 

 
A product found by multiplying the numerator of one fraction by the denominator of another fraction and the denominator of the first fraction by the numerator of the second.

cube
 

 
A solid figure with six square faces.

cylinder
 

 
A three-dimensional figure having two parallel bases that are congruent circles.

Information that is gathered

decimal number

degree

A unit of measure of an angle

denominator

The bottom part of a fraction.

dependent events

Two events in which the outcome of the second is influenced by the outcome of the first.

diagonal

The line segment connecting two nonadjacent vertices in a polygon. 

diameter

The line segment joining two points on a circle and passing through the center of the circle. 

difference

The result of subtracting two numbers. 

digit

distributive property

a(b + c) = ab + ac

dividend

In a / b= c, a is the dividend.

divisor

In a / b = c, b is the divisor.