# Math Vocabulary

Word Definition Examples
S    Sample Space In probability, all the possible ways that an event can happen.
Scalar A quantity that represents a magnitude. It can be represented by a real number.
Scale The distance between two consecutive tick marks on the x- and y-axes of a coordinate grid. When graphing, an appropriate scale must be selected so that the resulting graph will be clearly shown.
Scalene triangle A triangle with no sides congruent All sides are a different length Scatter plot A graph that relates ordered sets of data.  Scatter plots frequently have dots or x's Scientific Notation A number expressed in the form a x 10n where n is an integer and 1 < a < 10. For a number between 0 and 1, the exponent n will be a negative. 3450 = 3.45 x 103

0.052 = 5.2 x 10-2

Sector of a circle The portion of the interior of a circle intercepted by a central angle. Like a slice of a round pie
Segment Part of a line consisting of two endpoints and all the points between them
Semicircle Exactly half a circle
Sigma Σ σ Greek letter used in math and statistics problems
Similar Figures Figures that have the same shape, but not the same size. Same angles, proportional sides
Similar Triangles Triangles that have the same angles, but not necessarily the same size. Same shape
Similarity ratio The ratio of the lengths of corresponding sides in a similar polygon.
Simple fraction A fraction that has one number in the numerator and one number in the denominator
 12 17
Simple Interest Interest calculated using the formula I = prt, where I is interest paid, p is principle, r is the interest rate charged, and t is the time period. The interest on \$300 at 5% per year for 4 years is I = prt = 300(.05)(4) = \$60
Simplify Combine all like terms that can be combined and get rid of parentheses to cut down on the number of terms in an expression 5 + 3 simplifies to 8
Sine The ratio of the length of the side opposite an angle and the hypotenuse in a right triangle side opposite divided by hypotenuse see Trigonometry
Skew lines Two lines that are not in the same plane. They do not intersect and they are not parallel.
Slope The measure of the steepness of a line. Slope is the change in y (up and down) divided by the change in x (left and right).
Slope is abbreviated m.
 slope = m = Δy Δx
Slope-Intercept form A linear equation written in the form y = mx + b, where m is the slope and b is the y-intercept y = 2x + 4
In algebra, it means to figure out what the variable stands for.
x + 5 = 7
so x = 2
Solution or root A number that makes an equation a true statement
Solution set The set of all numbers that satisfy an equation (make it true).
Space The set of all points.
Square A parallelogram with four congruent sides and four right angles All sides and angles equal
Square Root If a2 = b, then a is the square root of b. Square root is the opposite of square. 5 and -5 are square roots of 25
Square Numbers A square number or perfect square counts the objects that can form a square. In other words, it is the product of some integer with itself. Standard Form of a Polynomial When the degree of the terms (exponents) in a polynomial decrease from left to right. 5x3 + 3x2 - x + 8
Statistics The branch of mathematics that deals with the collection, analysis, interpretation, explanation, and presentation of data.
Straight angle An angle that measures 180°, a straight line.

x = 180°

Straightedge A ruler that doesn't have any markings on it used to draw lines where the exact length doesn't matter.
Subtraction Adding the opposite 7x - 3x = 7x + (-3x) = 4x
Supplementary angles Two positive angles whose measures add to 180 degrees. When adjacent (sharing a side) supplementary angles make a straight line. A + B = 180°
System of Linear Equations Two or more linear equations for which a common solution is sought. The solution is where the two lines cross when graphed.
Word Definition Examples
T     Table of Values A method for finding points that solve an equation so the equation can be graphed. You guess an x, then plug it into the equation to solve for the matching y value. Continue until you have enough (x,y) pairs to graph.
 y = 3x + 4 x y = 3x + 4 points -2 -2 = 3(-2) + 4 (-2,-2) -1 1 = 3(-1) + 4 (-1, 1) 0 4 = 3(0) + 4 ( 0, 4) 1 7 = 3(1) + 4 ( 1, 7) 2 10 = 3(2) + 4 ( 2,10)
Tangent The ratio of the length of the side opposite an angle and the side adjacent to the angle in a right triangle side opposite divided by side adjacent see Trigonometry
Term A grouping together of one or more factors (variables and/or number).
Multiplication or division connects letters to numbers in a term. Addition and subtraction symbols separate terms.

4xy is one term

3xy + 5x – 6
has three terms

Theorem A conjecture that is proven. In geometry, properties, postulates and theorems are used to prove other theorems
Theoretical Probability The calculated chance that something will happen based on the number of ways possible in tossing a coin, the theoretical probability of getting heads is:
Theta Θ θ Greek letter frequently used to represent angles
Translation When a graph is shifted in a horizontal or vertical direction.
Trapezoid A quadrilateral with exactly one pair of parallel sides. Two sides are parallel, other sides are not.
Trend Line A line on a scatter plot that can be drawn to pass through the points. The trend line shows the correlation between the two sets of data.
Triangle A polygon with three sides and three angles Triangular Numbers A triangular number or triangle number counts the objects that can form an equilateral triangle Trigonometry The study of the relationship between angles and sides in a triangle and the calculations based on them.
Truncated decimal A fraction, that when converted to a decimal ends with repeating zeros. Because math people are so lazy, they don't write the zeros or show them as a repeating digit. Ľ = 0.250000..... = 0.25
Two-Step Equation An equation that has two operations and requires two steps to solve. See Solving Simple Equations. 7x - 5 = 9 is a two-step equation
Word Definition Examples
U     Unbounded intervals Intervals with end points at + ∞ on the real number line used to define the domain of an inequality. See bounded intervals [a,∞) means x > a
(a,∞) means x > a, an open interval
(-∞,b] means x < b
(-∞,b) means x < b, an open interval
(-∞,∞) means the entire number line
Undefined terms Words, usually easily understood, that are not formally explained or defined. In geometry, point, line, and plane are underfined terms
Unit Circle A circle with a radius r = 1 and its center is at the origin. The equation is x2 + y2 = 1 See Trigonometry
Unknown The value represented by a letter in an equation. The unknown is also called the variable.
Word Definition Examples
V     Variable A letter or symbol that is used to represent a number. When a variable is used in an equation, the eqation can be solved to find the value of the variable. This value is the solution to the equation.

x
a
z

Variable expression A mathematical phrase that contains at least one variable 8 - x is a variable expression
Vector A quantity that has both magnitude and direction Example: 5 miles north
Vertex The point on a parabola where the arch turns. If the parabola opens up, the vertex is the smallest value of the function. Vertex The point on a triangle where the sides come together. The vertices of triangles are usually labeled with capital letters. Comments, questions, or you just need some help? Send an e-mail to Mrs. Shearer 