Addition Property
if a=b, then a+c=b+c
Subtraction Property
If a=b, then a-c=b-c
Multiplication Property
If a=b, then ac=bc
Division Property
If a=b, then a/c = b/c provided c doesn’t equal zero
Reflexive Property
a=a (any number is equal to itself)
Symmetric Property
if a=b, then b=a
Transitive Property
If a=b, then b=a
Substitution Property
If a=b, then a may be replaced by b in any expression or equation
Distributive Property
a(b+c)= ab+ac
Simplify/Combine Like Terms (CLT)
Measure of Angle ABD + Measure of Angle ABD = 2(Measure of Angle ABD)
Segment Addition Postulate
If A, B, and C are collinear, then point B is between points A and C if and only if AB+BC=AC
Angle Addition Postulate
D is in the interior of Angle ABC if and only if measure of angle ABD + measure of Angle DBC= measure of angle ABC
Linear Pair Postulate
If 2 angles form a linear pair, then they are supplementary angles
Vertical Angles Theorum
If two angles are vertical angles, then they are Congruent (and have equal measures)
Right Angles are Congruent
If angles are right Angles, then they are congruent
Definition of Congruence
If AB=CD, then Segment AB is congruent to Segment CD
Definition of Perpindicular
Lines that intersect to form a right angle
Definition of Angle Bisector
A ray that divides an angle into two congruent angles
Definition of a Right Angle
an angle whose measure is 90 degrees
Definition of Supplementary Angles
2 angles whose sum is 180 degrees
Definition of Complementary Angles
2 angles whose sum is 90 degrees
Definition of Segment Bisector
A segment, line, or plane that intersects a segment at its midpoint
Definition of Midpoint
The point on a segment that divides a segment into 2 congruent segments (or 2 equal segments)
Postulate
Things that we accept without proof