NAME_________________________________________DATE___________________
GEOMETRY
MRS. BINASO
CONGRUENT TRIANGLES III
ADDITION/SUBTRACTION POSTULATES
In each of the problems below, you are asked to find the sum or difference of two line
segments or two angles. If it is not possible to find this sum or difference, simply write
"no answer" after the problem.
1. A
D
2.
A
B
E
a)
b)
c)
d)
B
C
AE + EC = ?
AC  EC = ?
BC + CD = ?
BD  BE = ?
E
a)
b)
c)
d)
D
<EAD + <DAB = ?
<EAB  <DAB = ?
<AEC  <BCE = ?
<ADE + <ADB = ?
In each of the problems below, write a valid conclusion.
3.
4.
A
B
A
C
F
E
D
B
D
C
E
Given: <BAD  <CDA
<BAE  <CDE
Conclusion: ?
Given: AF  CD
FE  BC
Conclusion: ?
5.
C
D
C
6.
A
F
E
D
A
E
F
B
B
Given: AE  ED
BE  EC
Conclusion: ?
Given: BE  CD
DF  EF
Conclusion: ?
C
In each of the following, write a valid two-column proof.
7. R
8.
E
A
S
A
B
C
F
T
Given: AE  DF
<A  <D
AC  DB
Prove: AEB  DFC
Given: AS  RT
A is the midpoint of RT
Prove: RAS  TAS
9.
10.
E
C
D
B
C
D
A
F
A
F
B
E
Given: ED  DA
BA  DA
DC  AF
<E  <B
Prove: EDF  BAC
Given: DC  DE
<x  <y
<z  <w
Prove: AE  AC