Preparing for the Regents Examination Geometry, AK

12. BAC EDF (CPCTC)
13. ___
ED ___
AD (Alternate interior angles are
congruent)
14 1. ___
BE bisects ABC.
2. 1 EBC
3. m1 mEBC
4. ___
CE bisects DCB.
5. 2 ECB
6. m2 mECB
7. m1 m2 90
8. mEBC mECB 90 (Substitution
postulate)
9. m1 m2 mEBC mECB
10. m1 mEBC 90
11. m2 mECB 90
12. ABC and DCB are right angles.
13. BA ___
BC
14. CD ___
BC
15. BA CD (Two lines perpendicular to the
same line are parallel.)
15 1. 1 3
2. m1 m3
3. 2 4
4. m2 m4
5. m1 m2 m3 m4 360
6. m1 m1 m2 m2 360
or 2(m1) 2(m2) 360
7. m1 m2 180 (Division
postulate)
8. −−−
AD −−
BC (Interior angles on the same
side of the transversal are
supplementary.)
9. m1 m1 + m4 m4 360
or 2(m1) 2(m4) 360
10. m1 m4 180
11. ___
AB ___
CD
16 1. D is the midpoint of ___
CF and of ___
BE .
2. ___
CD ___
DF
3. ___
BD ___
DE
4. ___
FC ___
FC
5. CBD FDE (Vertical
angles are
congruent.)
6. CBD FDE (SAS SAS)
7. EFD DCB (CPCTC)
8. ___
AC ___
FE (Alternate interior angles are
congruent.)
17 1. 1 2
2. AFC DCF (Supplementary angles
of congruent angles are
congruent.)
3. ___
EF ___
CB
4. ___
FC ___
FC
5. ___
EF ___
FC = ___
BC ___
FC
6. ___
EC ___
BF
7. ___
AF ___
CD
8. AFB DCE (SAS SAS)
9. ABF DEC (CPCTC)
10. ___
AB ___
ED (Alternate interior angles
are congruent.)
18 1. ___
AE ___
FC
2. ___
EF ___
EF
3. ___
AE ___
EF ___
FC ___
EF
4. ___
AF ___
CE
5. ___
DE ___
AC
6. DEA is a right angle.
7. ___
BF ___
AC
8. BFC is a right angle.
9. DEA BFC (Right angles are
congruent.)
10. ___
DE ___
BF
11. AFB CED (SAS SAS)
12. ______
AEFC
13. BAF DCE (CPCTC)
AB ___
DC
14. ___
9-3 Properties of Parallel
Lines
(pages 182–185)
1 (1) same-side exterior angles
2 (2) 2, 3, 6, 7, 10, 11, 14, 15
3 m1 m4 m6 m7 60;
m2 m3 m5 120
4 m1 m4 m5 m8 135;
m2 m3 m6 m7 45
5 ma md mg 65;
mb mc me mf 125
6 w y 70; x z 110
7 a 8x 6x 3 0 180
x 15
b 2x 1 0 5x 47
x 19
m3 2(19) 10 48
9-3 Properties of Parallel Lines 45