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Segment -
Line Segment
A line segment is the
finite piece of line that
connects two
points in space.
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Semiannual
A term often used in
Algebra money problems, semiannually means twice a year.
For information on how to solve compound interest problems,
check out my lessons on
Exponentials and Logarithms. |
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Sequence
A sequence is a list
of numbers that typically changes according to some sort of
pattern.
A
finite sequence
example: 1,
3,
5,
7,
9
An
infinite sequence
example: 1,
4,
9,
16,
25, ...
For more info on sequences, check out my
lessons on
Sequences & Series. |
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Series
A series is the
sum of a
sequence.
Example:
1 +
3 +
5 +
7 +
9 =
25
For more info on sequences, check out my
lessons on
Sequences & Series. |
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Set
A
set is a group of objects:
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Similar
Triangles
Similar triangles are
triangles whose
corresponding angles are
congruent and whose
sides are
proportional (see the equivalent fractions
to the right).
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Sine
From trigonometry, the
sine of an angle (in the
picture below) is the ratio of the
opposite side to the
hypotenuse:
For more trig info, check out my reference sections on
The Trigonometry of
Circles and The
Trigonometry of Triangles. |
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Slope of
a Line
Basically, the slope
of a line tells us how steep a line is and whether
it's going up or down (increasing or decreasing).
The slope is found by looking at the
rise over the
run.
For more specific info on how
to find slopes, check out my
Algebra lessons on lines. |
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Snub
Cuboctahedron
The snub
cuboctahedron is created by either truncating
(cutting off) tips
of the
cube or the
octahedron.
Properties of the snub cuboctahedron
38 total
faces:
32 equilateral
triangles and 6 squares
24 vertices where each is 4 triangles and 1 square
60 edges
Dihedral angle:
142 degrees, 59
minutes for the sqr-tri angle and
153 degrees, 14 minutes for the tri-tri angle
For more info about
polyhedra, check out my
Platonic solids gallery. |
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Snub
Icosidodecahedron
The snub
icosidodecahedron is created by either truncating
(cutting off)
the
dodecahedron or the
icosahedron.
Properties of the snub icosidodecahedron
92 total
faces:
80 equilateral
triangles and 12 regular pentagons
60 vertices where each is 5 triangles and 1 pentagon
150 edges
Dihedral angle:
152 degrees, 16
minutes for the pent-tri angle and
164 degrees, 11 minutes for the tri-tri angle
For more info about
polyhedra, check out my
Platonic solids gallery. |
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Sphere
A sphere is a three
dimensional
circle. Imagine putting a
line through the widest
part of a circle and spinning it.
This would give you a sphere. |
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Square
Numbers
A square number is the
answer when you take an
integer and multiply it to itself:
Here's a partial list of square numbers:
0,
1,
4,
9,
16,
25,
36,
49,
64,
81,
100,
121,
144,
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Square Root
Here is how we write a
square root... It's made up of a radical sign and
something inside called the
radicand.
The square root of a
number (the radicand) is a
number that produces the
radicand when
it is squared.
Example:
To learn more about radicals,
check out my
Radicals Review lesson. |
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Subset
A subset is a
set
whose members are part of a bigger set.
Example: The set B is a
smaller set whose members are part of the bigger
set A:
Here's how we write it...
The "U"
lying on its side is the symbol for "is
a subset of."
So, this says that the
set B is a subset of
the set A. |
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Subtrahend
When you do a
subtraction problem, the subtrahend is
the number you are taking off:
8 -
5 =
3
For more info, check out my
Subtraction Lessons. |
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Sum
In an addition problem
like
2
+
3 =
5,
the sum is the
answer.
For more info, check out my
Addition Lessons. |
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Summation
A summation is a fancy
notation to represent a
series (a list of things that you
want to add together.)
Here's an example:
The complete description is pretty long... If you want
more than this, check out my
Summations Algebra Lesson on Sigma Notation. |
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Supplementary Angles
In the picture on the right,
angles A and
B are supplementary
angles because their measures add up to
180 degrees:
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Supplement of an Angle
Working from the idea
of supplementary angles in the definition
above this,
the supplement of an
angle B is whatever
size is necessary so that, if you stick the two
angles
together, they make a 180
degree angle.
To find the
supplement of an
angle, just subtract from 180...
Example: Find the supplement of
angle B whose measure
is 40 degrees:
180 -
40 =
140... So, the
supplement is
140 degrees.
Easy! |
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Symmetry
Having symmetry (or
being symmetric) means that something is a mirror
image over a line in space.
Look at the picture on the right... The
left half is a perfect
mirror image of the right half
over that yellow line.
(Ignoring the color difference, of course.)
You can say that this image is symmetric with
respect to the line...
Or you can say that this image is symmetric over the
line (more casual).
The line is called the
axis of symmetry. |
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System of
Equations
A system of equations
is when you have more than one
equation AND more than one
variable to solve for (the unknowns).
Example:
2x -
5y
= 22
7x +
3y =
-5
For information on how to solve systems of equations,
check out my
Systems of Equations Lessons for 2x2's and my
Systems of Equation Lessons for 3x3's. |
