are two line that
intersect to form right angles
of a segment is a line,
segment or ray that is perpendicular to a
segment at its midpoint
is a ray that divides an angle
into two congruent angles
 Deductive
Reasoning is a process of reasoning
logically from given facts to a conclusion.
 Addition
Property of equality
if a=b then a+c=b+c
 Subtraction
Property of equality
if a=b then a-c=b-c
 Multiplication
Property of equality
if a = b then ac = bc
 Division
Property of equality
if a=b then a/c = b/c c≠0
 Substitution
Property– if a=b, then b can
replace a in any expression
 Distributive
 Reflexive
Property – a(b+c) = ab + ac
Property AB = AB
 Symmetric Property if AB = CD then CD = AB
 Transitive Property if AB = CD & CD = EF then
AB = EF
 Draw
two intersecting lines.
 Fold the sides of <1 onto <2. What do you
notice?
 Fold the sides of <3 onto <4. what do you
notice?
 Make a conjecture about the angles formed
by two intersecting lines.
1
3
4
2
1
3
4
2
 Vertical
angles – two whose sides are
opposite rays.
 Adjacent angles – two coplanar angles with a
common vertex, no common interior points.
 Complementary
angles – two angles , the sum
of whose measure is 90.
 Supplementary angles – two angles, the sum
of whose measures is 180.
 Vertical
Angles Theorem – Vertical angles
are congruent.
 Congruent
Supplements Theorem – If two
angles are supplements of congruent angles
(or of the same angle), then the two angles
are congruent.
 Congruent
Complements Theorem – If two
angles are complements of congruent angles
(or of the same angle, then the two angles
are congruent.