Download - LECTURE2-5
-
8/17/2019 LECTURE2-5
1/7
Lesson 2-5: Proving Lines Parallel 1
Lesson 2 - 5
Proving LinesParallel
-
8/17/2019 LECTURE2-5
2/7
Lesson 2-5: Proving Lines Parallel 2
Proving Lines Parallel - Postulates & Theorems
If two lines are cut by a transversal and corresponding
angles are congruent, then the lines are parallel.
DC
BA
-
8/17/2019 LECTURE2-5
3/7
-
8/17/2019 LECTURE2-5
4/7
Lesson 2-5: Proving Lines Parallel 4
Proving Lines Parallel - Postulates &Theorems
If two lines are cut by a transversal and consecutive
interior angles are supplementary, then the lines are
parallel.
DC
BA
-
8/17/2019 LECTURE2-5
5/7
Lesson 2-5: Proving Lines Parallel 5
Proving Lines Parallel - Postulates &Theorems
If two lines are cut by a transversal and consecutive
exterior angles are supplementary, then the lines are
parallel.
DC
BA
-
8/17/2019 LECTURE2-5
6/7
Lesson 2-5: Proving Lines Parallel 6
xamples! Proving Lines Parallel
Find the value of x which will make lines a and lines b parallel.
4. 20Ans"ers! #$ 20 2. !0 ". #0
2$
80
2x
b
a#$
60
3x
b
a
%$
70
(x-20)
b
a $
60
3x
b
a
-
8/17/2019 LECTURE2-5
7/7
Lesson 2-5: Proving Lines Parallel 7
'ays to Prove T"o Lines Parallel
$how that corresponding angles are e%ual.
$how that alternative interior angles are e%ual.
$how that consecutive interior angles aresupplementary.
$how that consecutive exterior angles are
supplementary. In a plane, show that the lines are perpendicular to the
same line.