Chapter 1 flashcards
Straight Angles
Thm: If two angles are
straight angles, then they
are congruent.
Right Angles
Thm: If two angles are right
angles, then they are
congruent.
Angle/Segment
Bisector
Def: A bisector is a line that
divides an angle (segment)
into 2 congruent angles
(segments).
Angle/Segment
Trisector
Def: Trisectors are lines
that divide an angle
(segment) into 3 congruent
angles (segments).
Union
∪
not overlapping
separated
common
Intersection
∩ interlapping
Where they meet
Symbols
Chain of Reasoning
Truth Values
Line:
↔
AB
Ray:
→
AB
Segment:
─
AB
Statement: p→q
Converse: q→p
Inverse: ~p→~q
Contrapositive: ~q→~p
If statement is true, then
contrapositive is true
If converse is true, then
inverse is true
Collinear
Def: Points that lie on the
same line are collinear.
Noncollinear
Def: Points that do not lie
on the same line are
noncollinear.
Angles
Def: An acute angle is an angle whose
measure is greater than 0 but less than
90 degrees. Def:An obtuse angle is an
angle whose measure is greater
than 90but less than 180 degrees.Def: A
right angle is an angle whose measure is
90 degrees. Def: A straight angle is an
angle whose measure is 180 degrees.
What You Can
Assume
What You Can NOT
Assume

Straight lines and angles
 Collinearity of points
 Betweeness of points
 Relative positions of points
Right Angles
Congruent segments
Congruent angles
Relative sizes of segments
and angles
Midpoint
Def: A midpoint is a point
that bisects a segment.
Trisection point
Def: Trisection points are
two points that trisect a
segment
Post: An unproved assumption
Difference between
Postulate/Definition/Theorem
Def: States the meaning of a term or
idea
Thm: A statement that can be proved
Probability
Probability =
Number of winners/
number of possibilities