Download PPSection 1.6

Geometry: Section 1.6
Describing Pairs of Angles
What you will learn:
1. Identify complementary and
supplementary angles
2. Identify linear pairs and vertical angles
Let’s consider several special pairs of angles.
Complementary angles are two angles
whose measures have a sum of 90
Each angle is called a _____________________
of the
complement
other.
Supplementary angles are two angles
whose measures have a sum of 180
Each angle is called a _____________________
of the
supplement
other.
Example: Complete the chart.
45
27
45
90  x
117
180  x
3 x  7  5 x  18  90
8 x  25  90
angle  x
complement  90  x
sup plement  180  x
8 x  65
x  65  8.125
8
x  3(90  x)  110
x  270  3 x  110
4 x  160
x  40
x  40
90  40  50
Two angles are adjacent if
they share a common vertex and side, but
have no common interior points
B and J
ABC and HJK
J and DEG
GEF and DEG
A linear pair is two angles
that are adjacent and whose noncommon
sides form a straight line
***NOTE: The angles of a linear pair will be
________________.
supplementary
Two angles are vertical angles when
their sides form two pairs of opposite rays
1
1
1 and 2 are vertical angles
AME
BMD
BMA and DME
BMD and AME
6 x  18  x  3  180
7 x  15  180
7 x  195
x  195
7
We must be very careful when interpreting a diagram. There
are certain things you can conclude by looking at the diagram
and certain things you cannot conclude.
HW: pp 52 – 53 / 3 – 6, 8 – 16 even, 28, 32,
34, 36 – 42