Mathematical "A" Words
The absolute value of a number is the distance that number is from zero.
The absolute value of a positive number or zero is that number.
The absolute value of a negative number is the opposite of that number,
and the absolute value of zero is zero which is neither positive
|3| = 3, and |-3| = 3, |0| = 0 .
Both 3 and -3 are 3 jumps away from zero, so they have the same absolute
value of 3.
The absolute value bars | |,
act as grouping symbols. You must simplify any expressions within these
bars before finding the final absolute value.
Ex: |3-7| = |-4| =
A unit of area often used to measure plots of land. One acre is equivalent
to exactly 43,560 square feet, or 4,840 square yards, or 1/640 of a square
mile, or about 4,047 square meters.
An angle whose measure is between 0° and 90º. We like to think of them
as the "cute" skinny angles.
A number to be added.
Property of Equality
If a = b, then a + c = b + c. Add the same
thing to both sides of an equation and you still have an equation.
3 = 12/4
7 + 3 = 12/4 + 7
10 = 10
identity The number
zero. When you add zero to any number, you do not change its identity,
thus the name, additive identity.
Identity Property of Zero
For any number n:
n + 0 = n. If you add zero to any other number, you do not change
Inverse The number,
which when added to a number, gives a sum of 0. The additive inverse of
n is denoted -n. Also called opposite.
Property of Subtraction
For any numbers
a and b: a - b = a + -b. In words, subtracting
b is the same as adding the opposite of b.
Two nonstraight and nonzero angles with a common side interior to the
angle formed by the noncommon sides.
In a polygon, two sides with an endpoint in common.
In a polygon, endpoints of a side.
An expression that contains a variable alone or with numbers and operation
4x + 2
A sequence of steps that leads to a desired result.
Angles formed by two lines and a transversal whose interiors are not
between the two lines and are on different sides of the transversal.
Angles one and seven
are alternate exterior angles as are angles two and eight.
When the two lines cut
by the transversal are parallel, the alternate exterior angles will
Angles formed by two lines cut by a transversal. They are between
the two lines and on alternate sides of the transversal.
Angles three and five
are alternate interior angles as are angles four and six.
When the two lines cut
by the transversal are parallel, the alternate interior angles will
In a triangle or trapezoid, the segment from a vertex perpendicular to
the line containing the opposite side;
also, the length of that segment. In a prism or cylinder, the distance
between the bases. In a pyramid or cone, the length of a segment from
the vertex perpendicular to the plane of the base. Also called height.
of a triangle
The perpendicular distance from any vertex of a triangle to the side opposite
that vertex. Also called height.
A geometry in which points are represented by coordinates and where algebraic
methods of reasoning are utilized.
The union of two rays with the same endpoint.
The rays are the sides and the common endpoint is called the vertex. There
are many types of angles. See the definitions for zero angle, right angle,
straight angle, acute angle, obtuse angle, reflex angle.
The ray with points in the interior of an angle that forms two angles
of equal measure with the sides of the angle.
An angle measured from the horizontal plane downward from an observer's
eye to a given point below the plane.
An angle measured from the horizontal plane upward from an observer's
eye to a given point above the plane.
See angle of elevation.
The "if" clause of a conditional. Also called hypothesis.
The perpendicular segment from the center of a regular n-gon to one of
A path from one point (node) of a network to another point (its endpoints
A part of a circle connecting two points (its endpoints) on the circle.
Measure of the space inside a two-dimensional figure. Area is measured
in square units.
Model for Multiplication
The area of a rectangle with length l and width w is
l times w or a = lw.
The result of adding the n numbers in a data set and dividing the
sum by n. Also called the average or mean.
Property of Addition For
any numbers a, b, and c:
( a + b) + c = a + ( b + c ) = a + b + c. The positions
of the numbers do not change, the placement of the grouping symbols changes.
(1+2)+3 = 1+(2+3)
3+3 = 1+5
Property of Multiplication
For any numbers a, b, and c:
a( bc ) = ( ab )c = abc. The positions of the numbers do not change,
the placement of the grouping symbols changes.
3(4x5) = (3x4)5
3(20) = 12(5)
60 = 60
Computer software or calculator that enables geometric figures to be constructed
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A figure that is added to a given figure, often to aid in completing proofs.
A number representing
a set of other numbers determined by taking the sum of those numbers and
dividing by the number of them. Also called mean or arithmetic
A line of reference in a coordinate system. Plural: axes.
The line through the cone's vertex and the center of its base.
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