550P
parallel lines Lines in a plane that never
intersect. (p. 332)
parallelogram A quadrilateral with two pairs of
parallel sides. (p. 346)
pentagon A polygon with five sides. (p. 342)
pentagonal prism A prism with two parallel
pentagonal bases. (p. 362)
pentagonal pyramid A pyramid with a
pentagonal base. (p. 363)
percent (%) The ratio or comparison of a
number to 100. (p. 394)
perfect square A number whose square root is
a whole number. (p. 83)
perimeter The distance around a figure. (p. 462)
period A set of three digits set off by a comma
in a whole number. (p. 34)
permutation A selection of different items in
which the orderis important. (p. 278)
perpendicular bisector A line that is
perpendicular to a line segment and divides the
segment into two congruent parts. (p. 333)
perpendicular lines Lines that intersect to form
right angles. (p. 332)
pi (p) The ratio of the circumference of a circle
to its diameter. An approximate value of is
3.14, or. (p. 470)
place value The value of a digit depending on
its position, or place, in a number. (p. 38)
plane figure A two-dimensional figure that has
straight or curved sides. (p. 330)
polygon A closed plane figure made up of line
segments. (p. 342)
polyhedron A solid, or space, figure whose
faces are polygons. (p. 362)
population In a statistical study, the set of all
individuals, or objects, being studied. (p. 492)
power of a number The result of using a
number as a factor a given number of times.
An exponent is used to express the power.
103 10 10 10, or 1000. (p. 74)
prime factorization Expressing a composite
number as the product of prime numbers.
(p. 182)
prime number A whole number greater than 1
that has only two factors, itself and 1. (p. 180)principal The amount of money borrowed
or saved. (p. 434)
prism A solid figure with two faces called bases
bounded by polygons that are parallel and
congruent. (p. 362)
probability A branch of mathematics that
analyzes the chance that a given outcome will
occur. The probability of an event is expressed
as the ratio of the number of desired outcomes
to the total number of possible outcomes.
(p. 274)
proportion A number sentence that shows that
two ratios are equal. (p. 382)
protractor An instrument used to measure
angles. (p. 330)
pyramid A solid figure whose base is a polygon
and whose faces are triangles with a common
vertex. (p. 362)
Pythagorean Theorem In a right triangle, the
square of the longest side, called the
hypotenusec, is equal to the sum of the
squares of the legs aandb. (p. 409)
Q
quadrant A region of a coordinate plane. (p. 502)
quadrilateral A polygon with four sides.
(pp. 342, 346)
R
radius A line segment from the center of a circle
to a point on the circle. (p. 352)
random sample A subgroup or part of a total
group, each of which or whom has an equally
likely chance of being chosen. (p. 292)
range The difference between the greatest and
least numbers in a set of numbers. (p. 300)
rate A ratio that compares unlike quantities.
(p. 380)
rate of commission The percent of the total
amount of goods or services sold that is
earned by the seller. (p. 432)
rate of discount The percent taken off the
original, or list, price. (p. 426)
rate of interest The percent paid to the
depositor on the principal. (p. 434)
rate of sales tax The percent of the list, or
marked, price levied as tax. (p. 428)
ratio A comparison of two numbers or quantities
by division. (p. 376)22
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