DEFINITIONS
What does congruent mean?
Same measure
∠A and ∠B form a linear pair → they are supplementary
Linear Pair Theorem
If R is midpoint of AB, what is true?
AR ≅ RB
If AB ≅ BC and BC ≅ CD, what can you conclude?
AB ≅ CD
“Linear pair → congruent”
Wrong (should be supplementary)
What does supplementary mean?
Adds to 180°
AB + BC = AC
Segment Addition Postulate
If AB = 5 and AC = 23, find BC.
BC = 18
Name the property:
AB = BC and BC = CD → AB = CD
Transitive Property
Supplementary angles are always equal”
False
What does midpoint mean?
Divides a segment into two equal parts
m∠A + m∠B = 180 → angles are supplementary
Definition of Supplementary Angles
If one angle in a linear pair is 63°, find the other
117°
If two angles are supplementary to the same angle, what is true?
They are congruent
m∠A + m∠B = 180 → ∠A ≅ ∠B
Not always true
What is a linear pair?
Two angles that form a straight line.
R is midpoint of AB → AR ≅ RB
Definition of Midpoint
If AB ≅ BC, what can you say about their lengths?
AB = BC
If two angles are complementary to the same angle, what is true?
They are congruent
R is midpoint → AR + RB = 180
Wrong (mixing segments with angles)
What are the two parts of a proof?
Statements and reasons
AB ≅ BC → AB = BC
Definition of Congruent Segments
If two angles add to 90°, what are they?
Complementary
If two congruent angles form a linear pair, what is each angle?
90°
AB ≅ BC → AB + BC = AC
Missing Segment Addition Postulate