Mathematical "M" Words
In a rotation, the amount that the preimage is turned about the center of
rotation, measured in degrees from -180 (clockwise) to 180 (counterclockwise),
+/- m<POP', where P' is the image of P under the rotation and O is its
which are sometimes called turns, can also have magnitudes outside
the range of
-180 to 180 degrees, such as 720 degrees or
-500 degrees. The thing you want to remember is that you are going
around in a circle, and every circle has only 360 degrees. So a rotation
of -500 degrees is really just one complete, clockwise, revolution
of -360 and -140 degrees more.
of size transformation
In a size change, the factor by which the length of the preimage is changed,
A'B'/AB , where A' and B' are the images of A and B under the transformation.
Also called a size change factor or scale factor of size transformation.
of this size transformation is two, because AB=5 units and A'B'=10.
The lengths on the image A'B'C' are all two times larger than on the
The distance between any point and its image.
AB of circle O The
points of circle O that are on or in the exterior of angle AOB.
Three letters are used to identify major arcs.
An operation on a geometric figure by which each point gives rise to a
unique image. A correspondence between two sets of points such that each
point in the preimage set has a unique image, and each point in the image
set has exactly one preimage. Also called a transformation.
A rectangular array of rows and columns.
A number that
describes a set of other numbers. You get a mean, or average, as
it is commonly called, by taking the sum of the numbers being examined
and then dividing that sum by how many numbers were added.
For example: To find
the mean, or average, of 10, 9, 8, and 5 this is what you would do:
In the proportion
a/b = c/d, the numbers b and c.
Proportions used to always
be written with colons on a straight line as you see at the top
of our example. The word "means" meant "middle",
thus the two numbers in the middle were called the means. It made
perfect sense to those historical folks, but people today often
wonder why b and c are called the means because today
we usually write proportions as equal fractions with a horizontal
a and d are called the extremes. This is because "extremes"
meant "outside" and the a and d are on the
outer sides of the horizontally written proportion.
In any proportion, the product of the means equals the product of the
extremes. Some people learn this as "cross products are equal
in any proportion."
The dimension or amount of something, usually in a system of units.
The union of segments that join the midpoints of the sides of a triangle.
a triangle The
segment connecting a vertex of the triangle to the midpoint of the opposite
we see all of the medians of triangle CEN. The spot where they intersect,
pt R, is called the center of gravity, and is a perfect balance point
for the triangle. You can prove this by cutting out the triangle and
balancing it on the tip of a pin directly at point R.
A list of options from which a user of a computer can select an operation
for the computer to perform.
two- dimensional map of the Earth's surface named for Gerhardus Mercator,
the Flemish cartographer who first created it in 1569.
The basic unit of length in the metric system.
1 meter 1.09
system of measurement A
system of measurement based on the decimal system. Also called the international
system of measurement.
of a segment The
point on the segment equidistant from the segment's endpoints.
( mi ) A
unit of length in the US system of measurement equal to 5,280 feet. 1
A prefix meaning 1/1000.
A word name for 1,000,000.
A word name for 0.000001 or 10-6.
AB of circle O
The points of circle O that are on or in the interior of angle
The number a in a - b.
A line over
which a figure is reflected. Also called reflecting line.
symbol consisting of a whole number with a fraction next to it, when written
like this it means the numbers are being added.
number written as a mixed numeral.
The number which appears most often in a data set. The mode of the following
data set is 6 : 15, 6, 2, 6, 42, 6.
It is possible to have more
than one mode as in the set 1, 1, 3, 12, 4, 4. It is possible to have
no mode if no values appear more than once as in the set 1, 2, 3, 4.
of Fractions Property for
all numbers a, b, c, and f with b and f
not equal to 0:
||Just multiply the numerators
and then multiply the denominators.
Property of Equation
For all real nos. x, y and a,
If x = y, then ax = ay.
Property of -1 For
any real number x: -1 times x = -x.
Property of Zero
For any real number x: x times 0 = 0.
Identity Property of One
For any number
n times 1 = n.
*We like to say that multiplying a number by one causes it to retain
number by which a given number can be multiplied resulting in a product
equal to 1. Also called reciprocal.
Property of Division For
any numbers a, and b, with b not equal to 0:
a/b = a times 1/b. In words, to divide by a number is the same
as multiplying by its reciprocal.
Ex: To divide by 2
gives the same answer as multiplying by 1/2. 24 divided by 2 = 12 and
24 times 1/2 = 12.