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MAT091 Basic Math Skills
Chapter #12, Measurements & Geometry Vocabulary
In order to demonstrate that you know and understand the meaning of a word or phrase you
should be able to do each of the following:
1. Write a complete and correct definition for the word.
2. Recognize its definition (and identify the word or phrase defined).
3. Identify an example that illustrates the meaning of the word or phrase.
4. Make up an example to illustrate the meaning of the word or phrase.
Note: For some of the words below, an alternate definition is shown in brackets [ ] after the
standard definition. In many cases, these alternates simply use more familiar (less technical)
language, so they may be easier to understand. In other cases, the definition in brackets describes
the meaning from a slightly different perspective.
Conversion factor: a fraction which can be multiplied by a measurement to get a new
name for that quantity using different sized units
Compound units or mixed units: a measurement expressed as some number of one size
of units and some number of a smaller size of units {example: 5 ft 6 in)
S.I.: abbreviation for system Internationale, the official name of the Metric System of
measurement
kilo-: prefix meaning 1,000 (one thousand) hecto-: prefix meaning 100 (one hundred)
deca- (or deka-) : prefix meaning 10 (ten) deci-: prefix meaning 1 (one tenth)
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centi-: prefix meaning 1 {one hundredth) 100
milli-: prefix meaning 1 (one thousandth) 1,000
micro-: prefix meaning 1 (one millionth) l,000,000
mega-: prefix meaning l,000,000 (one million)
plane: a perfectly flat surface that has no edge boundaries {so it extends infinitely far)
line: a perfectly straight path that extends infinitely far in both directions
point: a specific location (usually represented by a dot, but the actual point has no length
or width or measurable size the way a dot does)
space: a 3-dimensional region
solids: 3-dimensional objects that have height as well as length and width; [shapes that are
not contained on just a flat surface]
Plane figures: 2-dimensional shapes that lie on a flat surface.
Line segment: the part of a line that is between two endpoints.
ray: a part of a line having one endpoint and extending infinitely far in one direction
Angle: a plane figure made up of two rays that share a common endpoint [or: a rotation of
a straight path from one position to another]
Vertex: the common endpoint of the two rays that make up an angle
Degrees: units of measurement for angles
Parallel: Two lines are parallel if they never intersect (cross) and the shortest distance
between the lines remains the same all the way along the lines.
Perpendicular: Two lines are perpendicular if they form 900 angles (right angles) where
they intersect (cross).
Right angle: an angle whose measure is 900
Acute angle: an angle whose measure is less than 900
Obtuse angle: an angle whose measure is greater than 900 but 0 less than 180
Straight angle: an angle whose measure is 180° (so the two rays form a straight line)
Complementary angles: two angles whose measures add up to 90
Supplementary angles: two angles whose measures add up to 180
Intersection: the point where lines, segments, or rays cross each other (or meet)
Polygon: a closed, convex, plane figure made up of straight-line segments that intersect
only at their endpoints
Triangle: a polygon that has exactly three sides
Quadrilateral: any polygon that has exactly four sides
Trapezoid: a quadrilateral that has one pair of parallel sides
Parallelogram: a quadrilateral that has two pairs of parallel sides
Rhombus: a parallelogram in which all four sides are the same length
Rectangle: a quadrilateral in which all four angles are right angles
Square: a quadrilateral in which all four angles are right angles and all four sides are the
same length
Pentagon: a polygon that has exactly five sides hexagon: a polygon that has exactly six
sides
Octagon: a polygon that has exactly eight sides
Circle: a plane figure made up of all the points that are the same distance from one point
(called the center of the circle)
Center: a point (inside the region enclosed by a circle or a sphere) which is the same
distance from every point on the circle or the sphere
Radius: the distance from the center (of a circle or sphere) to any point on the circle or
sphere; [Sometimes we refer to a line segment from the center to a point on the circle as a
radius, too.]
Diameter: the distance from a point on a circle (or a sphere) to the point all the way across
the circle (or sphere) on a line through the center; [sometimes we refer to a line segment all
the way across the circle, through the center, as a diameter, too.]
Height (of a triangle or trapezoid or parallelogram): the distance from a vertex to the base (a
side of the figure, usually the one that seems to be on the bottom) along a line that is
perpendicular to the base
Equilateral triangle: a triangle in which all three sides are the same length
Isosceles triangle: a triangle in which two sides are the same length
Scalene triangle: a triangle in which all three sides are different lengths
Right triangle: a triangle that contains a right angle
Hypotenuse: the longest side in a right triangle; [the side across from the right angle in a
right triangle]
Legs: the two shorter sides in a right triangle [the two sides that make up the right angle in
a right triangle].
Rectangular Solid: a 3-dimensional figure in which all the sides are rectangles.
Cube: a 3-dimensional figure in which all the sides are squares.
Sphere: a 3-dimensional figure made up of all the points that are the same distance from
one point (called the center) [a perfectly round ball].
Cylinder: a 3-dimensional figure which has circles on both ends (parallel to each other),
connected by straight sides; [a smooth tin can shape].
Perimeter: the distance all the way around the edge of a plane figure (usually a polygon).
Circumference: the distance all the way around the edge of a circle.
pi π: a number which is the ratio (quotient) of the circumference of any circle to its
diameter [Pi is an irrational number whose value is approximately (but not exactly) equal to
22
3.14 or
]
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Area: a measure of the amount of flat surface enclosed by a plane figure
Volume: a measure of the amount of 3-dimensional space enclosed by a solid (3dimensional shape)
Similar: having exactly the same shape (including the same angle measurements) , but not
necessarily the same size
Congruent: having exactly the same size and shape.
Chapter 1
=
"equals"
>
"is greater than"
<
"is less than"
≈
"approximately equals"
∙
multiplication
()
parentheses
[]
brackets
{}
braces
Chapter 4
:
colon (used in ratios)
Chapter 10
││
absolute value
Chapter 11
≠
"is not equal to"
Exponential Expressions and Scientific Notation
a n  a  a  a  aa (n factors)
1
an  n
a
0
a 1
Chapter 12
π
pi
GEOMETRY FACTS AND FORMULAS
There are 360° in a complete revolution (a full circle).
The sum of the angles in any triangle is 180°
Circumference of a Circle:
C = 2πr or C = πd
Area of a Rectangle:
A = L∙W
Area of a Triangle:
A = 1/2∙b∙h
Area of a Circle:
A = πr2
Volume of Rectangular Solid: V = L∙W∙H