Word  Definition  Examples  

A  
Absolute Value  Distance of a number from zero on a number line. Since distance is always positive, the absolute value of any number must be positive. Caution: be careful when taking the absolute value of a variable, since you may have several possible correct solutions. 
 5  = 5  5 = 5 

Acute angle  An angle that measures between 0 and 90 degrees
0° < x < 90° 

Acute triangle  All angles in the triangle are acute  A 40  60  80 triangle is acute  
Additive Identity  0  zero When you add zero to anything it does not change the value. 
0 is the additive identity in algebra because a + 0 = 0 + a = a 

Additive Inverse  A number and its opposite  When you add them they equal zero.  5 and 5 are inverses because 5 + (5) = 0 

Adjacent angles  Two coplanar angles with a common side, a common vertex, and no common interior points  
Adjacent arcs  Two arcs in the same circle that have exactly one point in common.  
Algebra  The study of equations using variables. At Capitan High School, the study of algebra is broken into Algebra 1 and Algebra 2.  
Algebraic expression  A collection of letters (variables) and real numbers (constants) combined using the operations of addition, subtraction, multiplication, division, and exponentiation.  
Alpha Α α  Greek letter frequently used to represent angles  
Alternate exterior angles  When two lines are cut by a transversal, the alternate exterior angles are on opposite sides of the transversal and the outside of the two lines  
Altitude  The height of an object measured perpendicular (90 degrees) from the bottom to the top  
Amplitude of a periodic function  Half the difference between the maximum and minimum values of the function  
Angle  The shape formed by two rays (called sides of the angle) with the same
endpoint (called the vertex of the angle).
In geometry an angle can be defined by the vertex or by the rays and vertex. The symbol for angle is ∠ 
∠M or ∠ LMN  
Angle bisector  A ray that divides an angle into two congruent (equal) angles  
Angle in standard position  An angle that has its vertex at the origin and its initial side along the positive xaxis  
Angle of Depression  An angle from the horizontal down to a line of sight  The angle between the viewer and something below them  
Angle of Elevation  An angle from the horizontal up to a line of sight  The angle between the ground and something above the ground  
Apothem  A line segment that is drawn from the center of a regular polygon perpendicular to one side of the polygon.  
Arc  Part of a circle  Exactly half the circle is called a semicircle.
Less than half is a minor arc and more than half is a major arc. 

Arithmetic Mean  The arithmetic mean of numbers is the sum of the numbers divided by how many numbers you added  also called the average  The mean of 3 and 8 is 5.5  
Arithmetic Sequence  A numerical pattern where the difference between consecutive terms is a constant  The arithmetic sequence 1, 4, 7, 10, 13, ... has a common difference of 3  
Associative Property  Changing the grouping of addends or factors does not change the sum or product. Grouping doesn't matter when adding or multiplying  (2 + 3) + 4 = 5 + 4 = 9 2 + (3 + 4) = 2 + 7 = 9 (2 x 6) x 5 = 12 x 5 = 60 

Asymptote  A line the graph of a function gets close to but does not cross  
Axis of Symmetry  The line about which you can reflect a graph onto itself also the vertical line containing the vertex of a parabola 
When you fold a graph on the axis of symmetry, both sides match  For the parabola, y = x^{2} + 4x  5 the axis of symmetry is the line x = b/2a = 2 

Word  Definition  Examples  
B  
BacktoBack Stem and Leaf Plot  A stemand leaf plot used to compare two related sets of data  
Bar Graph  A graph where data is shown in bars that are used to compare amounts. The length of each bar represents the frequency  
Base  In an expression of the form x^{n}, x is the base and n is the exponent.  
Best Fit Line  The straight line that most closely approximates the data in a scatter plot.  
Beta Β β  Greek letter frequently used to represent angles  
Binomial  Polynomial expression with two terms  bi means two  2x + 3  
Binomial Experiment  An experiment that has only two possible outcomes  Tossing one coin is binomial because you only get heads or tails  
Binomial Theorem  The expansion of (a + b)^{n} where n is a positive
integer is: (a + b)^{n}= C_{0}a^{n} + C_{1}a^{n1}b^{1 }+ C_{2}a^{n2}b^{2 }+ ... + C_{n1}a^{1}b^{n1 }+ C_{n}b^{n} 
(x + 3)^{2}= x^{2} + 6x + 9 is a binomial expansion  
Bounded intervals  Intervals with defined end points on the real number line used to define the domain of an inequality. See unbounded intervals  [a,b] means a < x < b, a closed interval (a,b) means a < x < b, an open interval [a,b) means a < x < b (a,b] means a < x < b 

Box and Whisker Plot  A diagram that divides a set of data into four parts: lower quartile, below the mean (average), above the mean, and highest quartile.  
Branch  Each piece of a discontinuous graph.  y = (x + 5)/(x5) has two branches and is discontinuous at x = 5 

Word  Definition  Examples  
C  
Calculus  The study of infinitely small changes in slope and area, used to solve complicated realworld problems that cannot be solved using Algebra, geometry, or Trigonometry.  
Central angle  An angle whose vertex is the center of a circle  
Centroid  The point in a triangle where the medians of the triangle intersect. Click here for an animated example of the centroid.  
Central tendency  The tendency of data to be grouped near the center of the data.  Measured using mean, median, and mode.  
Certain Event  An event whose probability is one (1) or 100%  Something that always happens  
Circle  The set of all points in a plane that are a constant distance of r from a given point called the center. If the center is at (h,k) and the radius is r, the equation of the circle is (xh)^{2} + (yk)^{2} = r^{2}  (x2)^{2} + (y3)^{2} = 5^{2} is a circle with center at (2,3) and a radius of 5  
Circular function  The trig functions, because they can be defined as points along the radius of the unit circle.  
Circle Graph  A graph that represents the frequency of data as slices of a circle. The size of each slice represents the frequency, usually recorded as a percent.  
Circumcenter  The point in a triangle where the perpendicular bisectors of the sides of the triangle intersect. Click here for an animated example of the centroid.  
Closed interval  An interval that includes both of its end points.  
Coefficient  The numerical factor when a term has a variable  a number that is multiplied by a variable in an equation or expression.  The number next to a letter  5y 5 is the coefficient and y is the variable 

Cofunction  In trigonometry, the function pairs: sine and cosine, tangent and cotangent, and secant and cosecant.  
Collinear  Points that lie on the same line  Points that all line up  
Combination  An arrangement or listing where the order is not important.  Picking three students out of a classroom  
Common factors  Numbers, variables, and any products formed from the prime factors that appear in all terms of an expression  For 2x^{2} 6x 2 and x are the common factors 

Common logarithm  A base 10 logarithm  
Commutative Property  Changing the order of addends or factors does not change the sum or product  Order doesn't matter when adding or multiplying  2 + 3 = 3 + 2 = 5
5 x 4 = 4 x 5 = 20 

Compass  A tool used to draw circles and parts of circles  
Complementary angles  Two positive angles whose measures add to 90 degrees 
A + B = 90° 

Completing the Square  One method used to solve a quadratic equation. Other methods include factoring and the quadratic formula.  
Complex fraction  A fraction where the numerator, denominator, or both has a fraction 


Complex Number  A number of the form a + bi, where a and b are real numbers and i is the square root of 1.  Also called an imaginary number  
Concave polygon  When a diagonal contains points outside the polygon.  
Congruent  Objects that are the same size and the same shape. The symbol for congruent is an equal sign with a squiggle over it.  
Conjecture  The conclusion reached in a math statement based on reasoning  a guess based on observations.  
Constant  a value or number that never changes  5 3.7 

Constant Term  A term that has no variable factor  a number in an equation that is not multiplied by a variable  A number that stands alone  7x + 3 3 is the constant term 

Construction  Using only a compass and a straight edge to draw a geometric figure.  
Continuous Data  Measures that change between data points  Things that could be measured at any time  they always exist  temperature, height, time, blood pressure, average grade  
Continuous Function  Function whose graph is an unbroken curve  it does not have any holes, gaps, or jumps  
Convex polygon  No diagonal contains points outside the polygon  all the vertices of the angles point away from the center of the polygon.  
Coordinate of a point  On a number line, it is the distance of the point from the origin. On a coordinate axit is is the pair (x, y) that defines the location.  
Coordinate pair  A pair of numbers of the form (x, y) that gives the location of a point in the coordinate plane.  
Coordinate Plane  Formed when two number lines intersect at right angles. The xaxis is the horizontal axis and the yaxis is the vertical axis. The two axes meet at the origin (0,0). Click here for another explaination.  
Coplanar  Points and lines that are in the same plane The VLA west of Socorro, NM, is a group of 27 radio telescopes that are coplanar. 

Correlation  A trend between two sets of data. A trend may show positive correlation (both sets of data get bigger together) negative correlation (one set of data gets bigger while the other gets smaller), or no correlation.  
Corresponding parts  Matching sides and angles in a polygon. For a simple game on corresponging parts in a triangle, click here.  
Corollary  A statement that follows directly from a theorem.  Once you prove a theorem, the corollary is easily proven.  
Cosine  The ratio of the length of the side adjacent to an angle and the hypotenuse in a right triangle  side adjacent divided by hypotenuse  see Trigonometry  
Coterminal Angles  Two angles that share two sides in standard position. The sum of the absolute values of the angles adds to 360°.  150° and 210° are coterminal angles  
Cubic Equation  An equation in the form ax^{3} + bx^{2} + cx + d = y, where a, b, c, and d are real numbers and a ≠ 0 
Largest exponent is 3  2x^{3 }+ 3x^{2} 5x + 7 = y  
Cycloid  A curve that represents a path traced by a fixed point on the circumference of a circle rolling along a line. Used in Trigonometry and Calculus.  x = at  a sin t y = a  a cos t for t any real number 
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