Page 95 - TB_6B

Learn about the relationship between parallel lines and alternate angles.

Measure the angles formed, KLO and POL, when 2 parallel lines, KM
and NP, intersect with QR.

70 80 90 100 710106102050130
110 100 80
60
What you need: 20 50130 120 14400 30 Protractor
160 1530014040
150

60 90 60 160
20

0 10 0 30 30 0 170
180170 10

180
0

Q

K LM

NO P

R

When 2 parallel lines intersect with a transversal, the alternate angles are
congruent. KLO and NOR are corresponding angles, and NOR and

POL are vertical angles. Therefore, KLO and POL are congruent.

Parallel lines and alternate angles

When 2 lines intersect with a transversal,
2 alternate angles are congruent if the 2 lines are parallel.
2 lines are parallel if the 2 alternate angles are congruent.

2 . Use the diagram on the right to fill in the blank.

a. If AB CD, m a = .

A aB

b. If m a = 50 , AB and CD are .

c. If AB CD, m b = . C b 50 D

d. If m b = 130 , AB and CD are .

84