Mathematics Glossary
 Middle Years
Maxine Stinka, Saskatchewan Education,
Curriculum and Instruction
Note: The
definitions included here are those that are used in the Saskatchewan
Education document "Mathematics 69: A Curriculum Guide for the
Middle Level".
Various mathematics dictionaries
may have different definitions. These definitions are designed
to be meaningful to middle level mathematics teachers.
Select the first letter of
the term that you wish to look for.
A  B
 C  D
 E  F
 H  I
 J  K
 L  M
 N  O
 P  Q
 R  S
 T  U
 V  W
 X  Y
 Z
R
radius
(plural: radii)
 the distance from the centre of a circle
to any point on the circle.
range
 in statistics, the difference between the
least and the greatest values in a set of data.
In more advanced statistics, it is considered the number of values
between the greatest and the least, inclusive, and is calculated
by the formula range = greatest  least + 1
rate
 a quotient used to compare two measures
in different units e.g. kilometres per hour.
ratio
 a quotient used to compare two or more quantities
of the same units of measure.
rational number
 see fraction
 any number that can be written in the form a/b
where a and b are integers and b cannot equal
0. It is a negative rational number if it is less than zero i.e.
either a or b, but not both, is negative.
ray
 half a line.
 i.e.: the portion of a line on one side of a particular point (the endpoint).
reciprocals
(multiplicative inverses)
 two numbers whose product is one.
reflection
(flip)
 a transformation
of a geometric figure that results in a mirror image
of it. The object and the image are equal distance from the line
of reflection.
reflex angle
 an angle whose measure is between 180^{0}
and 360^{0}.
regular polygon
 a polygon
with all sides and all angles congruent.
An equilateral or equiangular triangle is a regular polygon as
is a square.
repeating decimal
 a decimal number that contains a digit or
digits that repeat. eg. 1/3 = 0.333...
rhombus
rotation
(turn)
 a transformation
of a figure in which the image is formed by turning the figure
about a fixed point called the center of rotation
which may be inside or outside the figure.
Questions or comments about the glossary can
be directed to TheCentralizer@MathCentral.uregina.ca
or see About Us
page for more information.
