Download Vocabulary Flash Cards (part 2)

Ray
A ray has one endpoint and
extends forever in one direction.
RinhtAnnlP
Kignt angie
An angle that measures
90 degrees
A part of a line that has endpoints
and a finite ,ength
Segment Bisector
A point, ray, line, segment, or
plane that intersects a segment at
its midpoint.
conclusion
The part of a conditional
statement immediately following
the word then.
conjecture
An unproven statement that is
based on observations
Converse
formed by interchanging the
hypothesis and conclusion of the
original statement
Counterexample
A counterexample is an example
that shows that a conjecture is
false
Deductive Reasoning
Using logic to arrive at a
conclusion based on things that
are known to be true.
Hypothesis
The part of a conditional
statement following "If
Inverse
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Logically Equivalent
To negate both the hypothesis and
conclusion of a conditional
statement.
To make a con ecture based on a
J observations.
pattern of
2 statements are logically
equivalent if their truth values are
the same for all cases.
Is the exact opposite of the statement. Often the
word NOT is added or removed to form the
negation of a statement.
polygon
A geometric figure with three or
more line segments that only
intersect at their endpoints
proof
logical reasoning that uses definitions, facts,
postulates, theorems, and properties to prove
something to be true
Quadrilateral
A four-sided polygon
-i-k
A statement that can be
proven.
Theorem
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Triangle
A 3-sided polygon
Two-Column Proof
A formal proof in which statements are listed in one
column and the reasons for each statement are
listed in a second column.
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Vertical Angles
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A term which cannot be defined by using other
figures; point, line, and plane are the building
blocks of geometry
Tne common
endpoint of the 2
rays that form an ang|e
Two non-adjacent angles formed
by 2 intersecting lines. Vertical
angles are congruent.
In a right triangle, the sum of the squares of the
lengths of the legs equals the square of the
hypotenuse.
lf two angles form a linear pair
'
then they are supplementary.
Congruent Supplements
lf two an
9les are supplementary to
the S8me angle
(°r con9ruent
angles), then they are congruent.
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Complements Theorem
^two an9'es are complementary
to the same angle (or congruent
angles), then they are congruent.
Right Angle Congruence
Theorem
All right angles are
congruent.
Vertical Angles Theorem
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Point, Line, and Plane
Postulate 1
Through any two points there is
exactly one line.
Point, Line, and Plane
Postulate 2
Through any 3 noncollinear points
there is exactly one plane.
Point, Line, and Plane
Postulate 3
If two points lie in a plane, then
the line containing them lies in the
plane.
Point, Line, and Plane
Postulate 4
If two lines intersect, then they
intersect in exactly one point.
Point, Line, and Plane
Postulate 5
If two planes intersect, then they
intersect in exactly one line.