1. Geometry Triangle Proof Vocabulary Practice
For #1-6, provide a conclusion and a reason for the given information.
If nothing given, label something that doesn’t have to be given, and
then do the problem.
G H L R Y W
J M N T V
Given:△GHJ ≊ △NML Conclusion: Conclusion:
Reason: Reason:
A G C E J
H B
Given: AH || GB Conclusion:
Reason:
I U
Given: CU bisects IE
Conclusion: T F Reason: M
P Q
L K J N
Conclusion: Given: K is the midpoint
Reason: of LJ
Conclusion:

2. Geometry Triangle Proof Vocabulary Practice
For #1-6, provide a conclusion and a reason for the given information.
If nothing given, label something that doesn’t have to be given, and
then do the problem
A X
B V C
D T S U
Given: ABCD is a parallelogram Given: △TVS ≊ △UXS
Conclusion: Conclusion:
Reason: Reason:
A R S
G T
D W X
C Given: T is the midpoint of WS
Conclusion:
Given: AD bisects CG Reason:
Reason: I J
Y Z M
B F K L
Conclusion: Conclusion:
Reason: Reason:

3. Triangle Proof Vocabulary
Term What it gives us Example
1. Midpoint two congruent segments C
(sides)
D E F
Given: E is the
midpoint of
DF.
Conclusion: DE≊ EF
Reason: Definition of midpoint
2. Reflexive Property two congruent sides W X
(can be presumed
from picture if present)
Y Z
Conclusion: WZ≊ ZW
Reason: Reflexive Property
3. Vertical Angles two congruent angles R T
(can be presumed S
U V
Conclusion: <RSU ≊ <TSV
Reason: Vertical Angles
Segment Bisector two congruent segment A B
(sides) C
D E
Given: AE bisects DB
Conclusion: DC ≊ CB
Reason: Definition of segment bisector

4. Triangle Proof Vocabulary
Term What it gives us Example
5. Parallelogram two congruent segments or angles C D (opposite sides) or
(opposite angles)
F E
Given: CDEF is a parallelogram
Conclusion: CD≊ FE or <C ≊ <E
Reason: opposite sides(or angles)
are ≊
6. Parallel Lines two congruent angles W X (usually alternate interior
or corresponding)
Y Z
Given: WX || YZ
Conclusion: <XWZ ≊ <YZW
Reason: Alternate Interior Angles
Corresponding Parts of Congruent congruent sides
Triangles are Congruent(CPCTC) or R T
(triangles must be congruent first) congruent angles S
U V
Given(or proven already): △RSU ≊ △VST
Conclusion: RU ≊ TV or <RUS ≊ <VTS
Reason: CPCTC