Section 1.4 - AnglesHow do you measure, name and classify angles? What is the Angle Addition Postulate?
How do you identify angle pairs?
Chapter 1 Section 1.6
Angles
A figure formed by two rays that have the same endpoint.
The two rays are called the sides of the angle
The common endpoint is called the vertex.
Can be named as B, ABC or 1
I prefer ABC or 1
Make sure that the vertex is the
middle point.
Acute Angle – an angle measuring between 0 and 90 degrees
Right Angle – an angle measuring 90 degrees
Obtuse Angle – an angle measuring between 90 to 180 degrees
Straight Angle – an angle measuring 180 degrees
Classify these angles
Challenge!
You and your partner figure out how many angles there are
Postulate 1-8: Angle Addition Postulate
If point B lies in the interior of AOC, then
m AOB + m BOC =m AOC
If AOC is a straight angle and B is any point not on line AC, then
m AOB + m BOC =180
B
C
O
A
O
A
C
B
Example
The measure of angle AOB is x and the measure of angle BOC is x+3. The measure of angle AOC is 55 degrees. What is angle AOB and angle BOC?
C
B
A
O
Adjacent Angles – common side, common vertex, no common interior points
Complimentary Angles – two angles whose measures add up to 90
Supplementary Angles – two angles whose measures add up to 180
Adjacent Angles
In the diagram below, identify all types of the following:
Complementary Supplementary Vertical
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