Mathematical "D" Words
A ten-sided polygon.
The notation in which numbers are written using ten digits and each place
stands for a power of ten.
Ex: 34 means 3 tens
and 4 ones.
The system in which numbers are written in decimal notation.
The process of making justified conclusions.
A description that clearly and uniquely specifies an object or a class
A unit of measurements
equal to 1/360 of a complete circle.
of a major arc ACB of circle O
360 - the measure of arc AB.
of minor arc AB of circle O
The measure of the central angle AOB.
The divisor, or bottom number, in a fraction.
b in the fraction a/b.
Remember that a fraction is
a division problem. The top number, the numerator, is the number being
divided, the fraction bar is the division symbol, and the bottom number,
the denominator, is the number of equal parts that you are dividing the
EX: Say you have $24/8.
Twenty four dollars divided into 8 equal parts means there will be $3
in each part.
EX: If the fraction
has a numerator smaller than its denominator you might get a problem
like this: $3/4. Three dollars divided into 4 equal parts. Each of these
parts will have less than one dollar in it, in this case $.75.
*If the numerator
is greater than the denominator, the fraction is > 1.
**If the numerator is less than the denominator, the fraction
is < 1.
The property that between two elements of the set there is at least one
other element of the set.
set of Real Numbers is dense because between any two numbers you can
always find another number, just enlarge the view.
of a polygon
A segment that connects two vertices of the polygon but is not a side
of a polygon.
A triangle has no diagonals.
of a circle or sphere
A segment connecting two points on the circle or sphere and containing
the center of the circle or sphere, also the length of that segment.
The answer to
a subtraction problem.
the ten symbols, 0 1 2 3 4 5 6 7 8 9, used to write numbers from zero
The angle formed by the union of two half-planes with the same edge.
The lengths of the sides of a rectangle. The number of rows and the number
of columns in a rectangular array.
of a box
The lengths of three edges of the box which meet at the same vertex. Usually
referred to as length, width, and height.
of a rectangle The
lengths of two sides of the rectangle which meet at a single vertex. Usually
referred to as length and width.
of translation The
direction given by the vector from any preimage point to its image point
in a translation.
Figures which are congruent and have the same orientation.
A figure made up of points with space between them.
The study of points as dots separate from each other, and lines made up
of these points.
area on a calculator where numbers appear.
between two parallel lines The
length of a segment that is perpendicular to the lines with an
endpoint on each of the lines.
between two parallel planes
The length of a segment perpendicular to the planes with an endpoint
in each plane.
between two points
The absolute value of the difference of their coordinates on a coordinatized
from a point to a line
The length of the perpendicular segment connecting the point to
from a point to a plane The
length of the perpendicular segment from the point to the plane.
Property of Multiplication over Addition
For any numbers a, b,
and x : ax + bx = ( a + b )x and x( a + b) = xa
+ xb. Also called distributivity.
Property of Multiplication over Subtraction
For any numbers a,
b, and x : ax + bx = ( a - b )x and ( a - b ) = ax - bx. Also
The number in
a quotient which is being divided; a is the dividend in a/b.
The number by which you divide in a quotient; b is the divisor
in a/b. Also a number that exactly divides into
another number, referred to as a factor.
A polygon with twelve sides.
A polyhedron with twelve faces.