###
acute angle

angle whose measure is less than 90 degrees and more than 0 degrees

###
angle

two rays with a common endpoint

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bisect, bisector

a point that divides a segment into two congruent sections is this

###
chain rule

if p then q and if q then r, then if p then r

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collinear

points that lie on the same line are collinear

###
conditional statement

if p then q when p and q are declarative statements

###
congruent angles

angles that have the same measure

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congruent segments

segments that have the same length

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contrapositive

if not q then not p

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deductive structure

a system of thought in which conclusions are justified by means of previously assumed or proved statements

###
definition

states the meaning of the term or idea

###
endpoint

a segment is named in terms of this

###
hypothesis

the "if" part of the sentence (If p, then q)

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implication

conditional statement (If p, then q)

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intersection

(n) this of any two sides is a vertex of the triangle

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inverse

if not p, then not q

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line

made up of points, straight

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line segment

made up of points, straight, has a definite beginning and end

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minute

degree is divided into 60 of these (') which are divided into 60 seconds (")

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negation

ex. p then not p

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noncollinear

points that do not lie on the same line is this

###
number line

formed when a numerical value is assigned to each point on a line

###
obtuse angle

angle whose measure is more than 90 degrees and less than 180 degrees

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point

an amount of space, represented by dots

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postulate

assuptions, one of the four elements of the deductive structure

###
probability

number of winners/number of possibilities

###
protractor

used to measure angles

###
ray

made up of points, straight, begins at an endpoint and then extends infinitely far in only one direction

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right angle

angle whose measure is 90 degrees

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second

60 of these make up a minute

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straight angle

angle whose measure is 180 degrees, forms a straight line

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theorem

mathematical statement that can be proved

###
tick mark

indicate congruent angles and segments

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triangle

has three segments as its sides/ three angles

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trisect, trisectors

two rays that divide an angle into three congruent parts

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trisection points

two points at which the segment is divided

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two column proof

type of proof with two columns, one for statements and one for reasons

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venn diagram

useful tool in determining whether or not a conditional statement is true or false

###
vertex

endpoint of the angle

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