Lesson 8.1
Concept: How to identify parallel lines, adjacent
angles, congruent angles, vertical angles,
complementary angles,and supplementary
angles.
Parallel Lines: Lines in a plane which
never meet.
k
m
l
5
6
8
7
1
4
2
3
Lines k and l
are parallel.
How to identify vertical angles.
Vertical Angles: Congruent Angles (same size and shape)
that share a vertex and are opposite each other.
Vertical Angles
<1 and <3
<5 and <7
<2 and <4
<6 and <8
l
k
m
5
6
8
7
3
1
2
4
Adjacent Angles: Angles that share one side.
400
x0
Complementary Angles: Two
adjacent angles whose sum of
their measures is 900.
x + 40 = 90
- 40 - 40
x = 500.
1350
y0
Supplementary Angles: Two adjacent
angles whose sum of their measures
is 1800.
y + 135 = 180
- 135 - 135
y = 450.
1
2
4
3
5
6
8
7
If the measure of <1 is 300 and the measure of <8 is 1500…………….
Name 4 pairs of adjacent angles.
Find the measure of angles 2 through 7.
Are <6 and <7 supplementary?
Are <1 and <2 supplementary?