 # Glossary Entries

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 Parallel Given distinct lines in the plane that are infinite in both directions, the lines are parallel if they never meet. Two distinct lines in the coordinate plane are parallel if and only if they have the same slope. Parallel Lines Lines in the same plane that never intersect no matter how far they are extended. They are always equidistant (the same distance) from each other. Parallelogram A quadrilateral with two pairs of parallel and congruent sides. Pattern A design (geometric) or sequence (numeric or algebraic) that is predictable because some aspect of it repeats. Examples: Numeric pattern that adds 3s:4, 7, 10, 13, ...Algebraic pattern that adds one to the multiple:x, x2, x3,... Spirals in a cactus. Geometric Designs. Penny A coin with a value of one cent or 1/100 of a dollar. Pentagon A polygon with five sides and five angles. Percent A number expressed in relation to 100; represented by the symbol %(e.g., 40 parts out of 100 is 40%). Percent Decrease The magnitude of decrease expressed as a percent of the original quantity. Percent Increase The magnitude of increase as a percent of the original quantity. Percentile A value on a scale that indicates the percent of a distribution that is equal to it or below it. For example, a score at the 95th percentile is equal to or better than 95 percent of the scores. Perfect Square A whole number resulting from multiplying an integer by itself; a is a perfect square if a = n*n and n is an integer (e.g. 16=4*4 and 121=(-11)*(-11)). Perimeter The distance around a closed figure. Permutation A permutation of the set of numbers {1, 2,..., n} is a reordering of these numbers. Possible arrangements of a set of objects in which the order of the arrangement makes a difference. Example: Determine all the different ways five books can be arranged in order on a shelf. Perpendicular Two lines, segments, or rays that intersect to form right angles. Perpendicular Bisector A line, segment, or ray that is perpendicular to and bisects a line segment. Personal Reference Something that a person can refer to as a standard, for the purpose of comparison (e.g., knowing the width of your pinky finger is approximately 1 cm). Examples:The height of the room is about twice as tall as a student. The length of a fifth grader’s arm is about 2 feet. Phenomena Something that is observable. Singular Form: Phenomenon. Physical Model A physical model is a representation of something using objects. Physical Phenomena Problems in the physical world that involve math. Example: Acceleration due to gravity. Pi The ratio of the circumference of any circle to its diameter. Pi is an irrational number with an approximate value of22/7 or 3.14159. Pictograph A pictograph is a graph or chart that uses pictures to show data. Pint A customary unit used to measure capacity; 2 cups = 1 pint; 2 pints = 1 quart. The abbreviation for p[int is "pt." Place Value The value of a digit in a number based on its position (e.g., in the number 28, the 2 is in the tens place and the 8 is in the ones place). Plane A flat surface that extends infinitely in all directions. That flat surface is defined by a set of points. Plane Figure A figure that lies on a flat surface; it has length, width, perimeter, and area. Plot To locate a point on a coordinate plane. Plus A term that refers to addition or the symbol for addition. Plus Sign The symbol (+) used to indicate addition. Point An exact location in space represented by a dot. A point does not have any dimensions. Polar Coordinates The coordinate system for the plane based on r , q , the distance from the origin and q , and the angle between the positive x- axis and the ray from the origin to the point. Polar Equation Any relation between the polar coordinates (r, q ) of a set of points (e.g., r = 2cosq is the polar equation of a circle). Poll The results of a question or questions answered by a group of people. Polygon A closed-plane shape that has more than three or more sides. The shape is flat and has no depth. Examples are a triangle, square, and pentagon. Polyhedron A three-dimensional shape with a multiple number of sides. The figure will have four or more faces. Examples are a pyramid, cube, and dodecahedron. Polynomial In algebra, a sum of monomials; for example, x2 + 2xy + y2. The exponents must be positive. Population A group of people, objects, or events that fit a particular description; in statistics, the set from which a sample of data is selected. Positive Number Any number greater than zero or to the right of zero on the number line. Post Meridiem Afternoon; the times from 12 noon until 12 midnight; 12 noon is 12 p.m. The abbreviation for post meridiem is "p.m." Pound A customary unit used to measure mass; 1 pound = 16 ounces. The abbreviation for pound is "lb." Power An exponent (e.g., in the expression 38, 8 is the power and 3 is the base). Precise Exact in measuring; accurate. Precision A property of measurement that is related to the unit of measure used; the smaller the unit of measure used, the more precise the measurement is. Example:19 mm is more precise than 2 cm. Predict To be able to determine the next step or value (to make an educated guess), based on evidence or a pattern. Prediction An educated guess about an outcome. Pre-Image In transformational geometry, the figure before a transformation is applied. Preserved In transformational geometry, a property that is kept or maintained. Example:In a translation the shape and size (property of congruence) is preserved. Prime Factorization A way to show a number as the product of prime factors. Example: The prime factorization of 12 is 2x2x3. Prime Number A natural number that can only be divided by one and itself and give no remainder. The first ten primes are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29. Prism A three-dimensional solid that has two congruent and parallel faces that are polygons. Those parallel faces are called the bases. The rest of the faces are parallelograms. Probability The chance of an event occurring; the ratio of the number of favorable outcomes to the total number of possible outcomes; the probability of an event must be greater than or equal to 0 and less than or equal to 1. Example:P(rolling a 3) = the number of 3's on the faces / the total number of faces = 1/6. Problem Solving Strategies Various methods used to solve word problems; strategies may include, but are not limited to: acting it out, drawing a picture or graph, using logical reasoning, looking for a pattern, using a process of elimination, creating an organized chart or list, solving a simpler but related problem, using trial and error (guess and check), working backwards, writing an equation. Product The answer in a multiplication problem. For example, 6x3=18, 18 is the product of 6x3. Profit The amount of money left after expenses have been subtracted from income. Proof A valid argument, expressed in written form, justified by axioms, definitions, and theorems. Proper Fraction A fraction whose numerator is less than its denominator. Properties Characteristics of a shape or object (e.g., size, shape, number of faces, or ability to be stacked or rolled). Properties of Real Numbers Rules that apply to the operations with real numbers. Examples: Commutative Property: a + b = b + a or ab=ba, Associative Property: a + (b + c) = (a + b) + c or a(bc) = (ab)c, Distributive Property: a(b + c) = ab + ac, Identity: a + 0 = a or a*1=a, Inverse: a + (–a) = 0 Proportion An equation which states that two ratios are equivalent (e.g., 5/10=1/2 or 5:10 = 1:2). Proportional Reasoning Using the concept of proportions when analyzing and solving a mathematical situation. Example: If triangle ABC is similar to triangle XYZ and AB = 15 when sideXY = 75, find BC when YZ = 150. Proportionality The quality, character, or fact of being proportional. Protractor An instrument used to find the degree measure of an angle. Pyramid A polyhedron whose base is a polygon and whose other faces are triangles that share a common vertex . Pythagorean Theorem The mathematical relationship stating that in any right triangle the sum of the squares of the two legs is equal to the square of the hypotenuse (the longest side of the triangle). If a and b are the lengths of the legs and c is the length of the hypotenuse, then a2 + b2 = c2.

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