Transcript Lesson 3-4 Proving lines parallel,

Lesson 3-4 Proving
lines parallel,
Postulates and Theorems

Postulate 3-4 – If two lines in a plane are cut by a
transversal so that corresponding angles are congruent,
then the lines are parallel.

Postulate 3-5 – If there is a line and a point not on the
line, then there exists exactly one line through the point
that is parallel to the given line

Theorem 3-5 - If two lines in a plane are cut by a
transversal so that a pair of alternate exterior angles
are congruent, then the lines are parallel.
Postulates and Theorems

Theorem 3-6 - If two lines in a plane are cut by a
transversal so that a pair of consecutive interior
angles are supplementary, then the lines are parallel

Theorem 3-7 - If two lines in a plane are cut by a
transversal so that a pair of alternate interior angles
are congruent, then the lines are parallel

Theorem 3-8 – In a plane, if two lines are perpendicular
to the same line, then they are parallel.
Notes

Find the value of x and mVST so thatl || p
l
S
V
p
(3x – 4)°
B
(12x – 11)°
T
U
Notes

Find the value of x and mVST so thatl || p
l
S
V
p
(9x – 11)°
B
U
T
(8x +4)°