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