**Acute angle:** A positive angle measuring less than 90 degrees** **

**Additive inverse (opposite): **The additive inverse of any number **x** is the number that gives zero when added to **x**. The additive inverse of 5 is -5

**Area: **The number of square units that covers a shape or figure

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

**Circumference: **The boundary line of a circle

**Complementary angles: **Two angles whose sum is 90°

**Cone: **A three-dimensional figure with one vertex and a circular base

**Congruent: **Figures or angles that have the same size and shape

**Coordinate plane/system: **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.

**Coordinates of a point:** Each point in the coordinate plane can be specified by an ordered pair of numbers

**Cube:** A solid figure with six square faces

**Cylinder:** A three-dimensional figure having two parallel bases that are congruent circles

**Data: **Information that is gathered

**Decimal:** The numbers in the base 10 number system, having one or more places to the right of a decimal point

**Denominator: **The bottom part of a fraction

**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:** The ten symbols, 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. The number 215 has three digits: 2, 1, and 5

**Coefficient:** A constant that multiplies a variable

**Prism: **A solid figure whose bases or ends have the same size and shape and are parallel to one another, and each of whose sides is a parallelogram

**Variable: **A letter used to represent a number value in an expression or an equation

**Right Angle: **An angle whose measure is 90 degrees

**Ray:** part of a line, with one endpoint, and extending to infinity in one direction

**Supplementary angles:** Two angles are supplementary if their sum is 180 degrees

**Simple Interest:** Interest paid only on the original principal, not on the interest gained

**Dividend:** In **a / b = c**, **a** is the dividend

**Divisible: **Capable of being divided, especially with no remainder

**Divisor: **In **a / b = c**, **b** is the divisor

**Edge: **The line of intersection of two surfaces

**Endpoint:** Either of two points marking the end of a line segment

**Equation:** A mathematical statement that says that two expressions have the same value; any number sentence with an =

**Exponent:** A number that indicates the operation of repeated multiplication

**Factor:** One of two or more expressions that are multiplied together to get a product

**Fibonacci sequence:** The sequence of numbers, 1, 1, 2, 3, 5, 8, 13… in which each successive number is equal to the sum of the two preceding numbers

**Formula:** An equation that states a rule or a fact

**Improper fraction:** A fraction with a numerator that is greater than the denominator

**Integer:** The set of numbers containing zero, the natural numbers, and all the negatives of the natural numbers

**Mixed number:** A number written as a whole number and a fraction

**Mode:** A type of average; the number (or numbers) that occurs most frequently in a set of data

**Numerator:** The top part of a fraction

**Obtuse angle:** An angle whose measure is greater than 90 degrees

**Parallel:** Two lines are parallel if they are in the same plane and never intersect

**Perimeter:** The sum of the lengths of the sides of a polygon

**Inequality:** A mathematical expression which shows that two quantities are not equal

**Surface area:** For a three-dimensional figure, the sum of the areas of all the faces

**Slope:** The steepness of a line expressed as a ratio, using any two points on the line

**Translation: **A transformation, or change in position, resulting from a slide with no turn

**Square:** A quadrilateral with four equal sides and four 90 degree angles

**Scientific notation:** A method for writing extremely large or small numbers compactly in which the number is shown as the product of two factors

**Prime factorization:** The solution of an integer or polynomial into prime factors such that when multiplied together they give the integer or polynomial

**Prime number: **A number whose only factors are itself and 1

**Probability:** For an experiment, the total number of successful events divided by the total number of possible events

**Product:** The result of two numbers being multiplied together

**Proportion:** An equation of fractions in the form:

a/b = c/d

**Quotient:** The answer to a division problem

**Radius:** The distance from the center to a point on a circle; the line segment from the center to a point on a circle

**Remainder:** The number left over when one integer is divided by another

**Repeating decimal:** A decimal in which the digits endlessly repeat a pattern

**Sum:** The answer to an addition problem

**Triangle:** A three-sided polygon

**Volume:** A measurement of space, or capacity

**X-axis:** The horizontal axis in a Cartesian coordinate plane

**Y-axis:** The vertical axis in a Cartesian coordinate system

**Whole number:** The set of numbers that includes zero and all of the natural numbers

**Hypotenuse:** The side opposite the right angle in a right triangle

**Pythagorean Theorem:** The theorem that relates the three sides of a right triangle:

**Perpendicular:** Two lines are perpendicular if the angle between them is 90 degrees

**Polygon:** A closed plane figure made up of several line segments that are joined together

**Vertex:** The point on an angle where the two sides intersect

**Real number:** The combined set of rational numbers and irrational numbers**
Quadrilateral:** A polygon with 4 sides

**Reflection:** A transformation resulting from a flip

**Square root:** The square root of x is the number that, when multiplied by itself, gives the number, x