Seventh Grade
Math Vocabulary
Acute Triangle
A triangle whose angles all measure less than 90°
Examples
36
Golden
acute
triangle
72
72
Area of
Complex Shapes
The number of square units needed
to cover a given surface
Divide the shape into shapes
whose areas are easy to calculate
and then add (or subtract)
to find the area of the given shape
Example
1500
3000
The area of the given shape is:
1500 + 3000 = 4500 square units
Area of
Irregular shapes
The number of square units needed
to cover a given surface
Count the number of whole square units and combine
partial square units together to get a total area
Examples
The area is approximately 32 units²
The area is approximately 10 units²
Box & Whisker Plot
A graph that shows how far apart
and how evenly data are distributed
Example
68 is the median, 52 is the lower quartile, 87 is the upper quartile
18 27 34 52 54 59 61 68 78 82 85 87 91 93 100
Equiangular Triangle
A triangle with three congruent angles
(and also three congruent sides)
60
60
60
Equilateral Triangle
A triangle with three congruent sides
(and also three congruent angles)
Examples
Exponent Notation
A number written with a base an exponent
Examples
Exponent
2
2 8
3
Base
11
=
64
Exponent
The number that indicates how many times
the base is used as a factor
Examples
4  4444
3
4  444
2
4  44
4
8  88
2
base
Inequalities
(number line)
The graph of a mathematical sentence showing the
relationship between quantities that are not equal,
using <, >, <, >, or 
Examples
x2
x2
x4
x  2
Integer
The set of whole numbers and their opposites
Examples
Integers
2 2
0
12
Use the remaining integers to
Make every circle add to zero
Isosceles Triangle
A triangle with (at least) two congruent sides
The two congruent sides are called legs
The third side is the base
The angle formed by the legs is the vertex angle
Examples:
Vertex angle
leg
leg
base
Linear Equation
An equation that can be represented as a line
on the coordinate plane
Examples
x y 2
y  x3
y  2x  3
Multi-step Equations
An equation where you have to do more than one
operation in order to find the solutions
Examples
2 x  3  17
2 x  20
x  10
5 x  2 x  18
3x  18
x  6
3( x  1)  15
3x  3  15
3x  12
x4
Obtuse Triangle
A triangle containing exactly one obtuse angle
(an angle greater than 90 degrees)
 90
Opposite
Two numbers (represented by points on the number
line) that are the same distance from zero
and are on opposite sides of zero
Examples
The opposite of 0 is 0
8 and -8 are opposites
1
1
 and
are opposites
2
2
4 and -4 are opposites
Percents
(above 100, below 1)
A percent is a ratio that compares a number to 100
Percent means “per hundred”
Examples
.7 10
7
.7% 
 
100 10 1000
.
A percent above 100 means
you have more than a whole:
2
1 5 250
 
 250%
2 2 100
Pi
(approximation)
The ratio of the circumference of a circle to
the length of its diameter
C  31.4cm
Examples
d  10cm
31.4
10


3.14
C

d
d  4cm
C  12.56cm
12.56

 3.14
4
3.14159265358979323846264338327950288419716939937510582...
Rational Numbers
a
Any number that can be expressed as a ratio
b
where a and b are integers and b  0
Decimals representing rational numbers
either terminate or repeat
Examples
6
6
1
1
 .3
3
1
.1 
9
Real Numbers
2
3
0
0
1
2
.2 
9
2

3
Rational Numbers
Integers
Whole
numbers
Natural
numbers
( is irrational)
Irrational
numbers
Regular Polygon
A polygon in which all sides
and all angles are congruent
Examples
pentagon
Equilateral
triangle
heptagon
hexagon
square
decagon
octagon
nonagon
Right Triangle
A triangle with exactly one right angle
Examples
90
90
Scale Factor
The common ratio for pairs of
corresponding sides of similar figures
The ratio used to enlarge or reduce objects
Examples
10
8
4
5
6
3
The scale factor is 2
6 8 10
 
2
3 4 5
Models: if a car is 204” in length
and the length of a model
of the car is 12” long,
12
1

the scale factor would be 204 17
Scalene Triangle
A triangle with no congruent sides
Its sides are all different in length
(Its angles are also all different in size)
Examples
abc
10
14
20
Scatter Plots
A graph of plotted points that attempts
to show a relationship (correlation)
between two variables
Examples
This data shows a
positive correlation:
As x increases,
so does y
This data shows a
negative correlation:
As x increases,
y decreases
This data shows
no correlation
Similarity
Figures that have the same shape,
but not necessarily the same size
Examples
Similar
25
25
Similar
2
5
65
4
2 5

4 10
65
Similar polygons have congruent
corresponding angles
10
Similar polygons have
corresponding sides that form
equivalent ratios (proportions)