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ANGLES, ANGLES, ANGLES
Naming AnglesMeasuring AnglesClassifying Angles
The Angle Addition Postulate
An angle is formed by two rays with a common endpoint called a vertex.
C - vertex
D
E
CD and CE are the rays that form the sides of theangle. C is the commonendpoint, or vertex.
There are four different ways to name an angle: #1:
-by its vertex with in front of the capitalletter
C
D
E
This is C.
There are four different ways to name an angle: #2:
-by a number placed inside the angle with in front of the number
C
D
E
This is 3.
3
There are four different ways to name an angle: #3:
-by three letters - a point on one of the raysfollowed by the vertex of the angle followed by a point on the other ray with in front the threecapital letters.
C
D
E
This is DCEor ECD.
There are four different ways to name an angle: #4:
-by a lower case letter placed inside the angle with in front of the lower
case letter.
C
D
E
This is a.
a
Click on the correct name for the angle shown.
T
E
J
D
d TEJ
JTE
etj
Think about capital letters and lower case letters.
Think about what the middle letter should be.
WHITE NOTE CARD:
ANGLES
Formed by two rays with a common endpoint called a vertex. BC and BG are the rays, B is the vertex
Named by: - the vertex (a capital letter) B - a number placed inside the angle 8 - three capital letters - a point on one ray followed by the vertex followed by a point CBG on the other ray; vertex always in the middle GBC - a lower case letter placed in side the angle
All of these start with .
B
C
G
8
Angles are measured in degrees using a protractor. The protractor is used to
measure the opening between the two rays that make up the angle.
Angles can be classified in four different ways:
Acute angles - angles that measure less than 90º
Right angles - angles that measure 90º
Obtuse angles - angles that have a measure greater than 90º but less than 180º
Straight angles - angles that measure 180º
True or False - Click true or falsenext to each statement.
TRUE / FALSE - All right angles are congruent.
TRUE / FALSE - All obtuse angles are congruent.
TRUE / FALSE - An obtuse angle and an acuteangle could be congruent.
TRUE / FALSE - Three acute angles could be congruent.
Continue – all finished with the True / False questions.
WHITE NOTE CARD:
ANGLE CLASSIFICATION
Angles can be classified in four different ways:
Acute angles - angles that measure less than 90º
Right angles - angles that measure 90º
Obtuse angles - angles that have a measure greater than 90º but less than 180º
Straight angles - angles that measure 180º
If R is in the interior of PQS, then m PQR + m RQS = m PQS.
Q
P
S
R
If R is in the interior of PQS, then m PQR + m RQS = m PQS.
Q
P
S
RSo, if R is in the interior of the big angle, then the sum of the measures of the two smallerangles will equal that big angle.
If R is NOT in the interior of PQS, then m PQR + m RQS m PQS.
Q
P
S
R
If m PQR + m RQS = m PQS, then R is in the interior of PQS.
What does this mean? Think about thesecond part of the
Segment Addition Postulate.
COLORED NOTE CARD
ANGLE ADDITION POSTULATE
If R is in the interior of PQS, then m PQR + m RQS = m PQS.
If m PQR + m RQS = m PQS, then R is in the interior of PQS.
Q
P
S
R
