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### A Glossary of Mathematical Terms - P

#### Palindrome

A number wich is the same left to right and right to left: 34543.

#### Parabola

One of the conic sections.
V: vertex;
F: Focus.

#### Parallelepiped

A solid whose faces are all parallelograms.

#### Parallelogram

A quadrilateral with opposite sides that are parallel.

#### Parenthesis (pl.parentheses) ( ) (round brackets)

Simbols used, for example, in algebraic expressions.

A 15-sided polygon.

#### Pentagon

A five-sided polygon.

#### Percent

Part of 100.
Percent to decimal: 34% = .45;
Decimal to percent: 2.7 = 210%.

#### Percentile

A point that divides a set of data (arranged in ascending or descending order) into two parts: about n% of the data lie before the nth percentile, the rest is above it. The 50th percentile is also called the 2nd quartile.

#### Perfect square

A whole number that is the square of an integer.

#### Pie chart

See Circle graph.

#### Place value

It refers to the value of each poisiton or place in a number. In 3245 3 is in the thousands place.
Names of places values: ... billions (109), hundred millions (108), ten millions (107), millions (106), hundred thousands (105), ten thousands (104),  thosands (103), hundreds (102), tens (101), ones (100), tenths (10-1), hundredths (10-2), thosandths (10-3), ten thousandths (10-4), ...

#### Plane of symmetry

A plane taht divides a 3-D object into 2 parts, each a mirror image of the other.

#### Polarity of a variable

The positivity or negativity of the variable.

#### Polygon

A closed 2-D figure made up of line segments (at least 3).

#### Polyhedron

A 3-D object that has polygons as its faces. The intersection of any two faces is an edge.

#### Polynomial

An expression consisting of the sum of one or more monomials.

#### Power

A power: ab; a is the bases, b is the exponent (sometimes b itself is called the power).

#### Prime number

An integer greater than 1 whose only positive factors ar 1 and the number itself.

#### Prism

A solid with two congruent polygons as bases in parallel planes. All other faces are parallelograms. It is named according to the shape of its bases.

#### Product

See Multiplication.

#### Product set

The set of all couples formed by pairing every member of one set with every member of another set.

See Fraction.

#### Proper subset

A subset different from the null set and the parent set.

#### Proportion

An equality of two ratios: a : b = c : d.

#### Protractor (circular or semicircular)

A circular (or semicircular) device subdivided into 360 (or 180) equal parts, and used for measuring angles.

#### Pyramid

A solid with a polygon as base and all other faces triangular with a common vertex.

#### Pythagorean triple

A set of three natural numbers that can be the sides of a polygon.

first published on september 01 2003 - last updated on september 01 2003