All About Angles!

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All About Angles!
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1.
Move through the topics at your own pace
The Basics of Angles
3.
Acute Angles
Right Angles
2.
5.
Obtuse Angles
Reflex Angles
The numbers are just suggestions.
The Project
4.
6.
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Right Angles

• A right angle is a square corner.
• A right angle is 90.
• A right angle looks like this

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More About Right Angles!

• Only right angles have a square at the vertex.
• Right angles can be rotated many ways.
• But as long as there is a square corner, the
  angle is a right angle.

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Lets Take a Quiz!

• Is this a right angle?

Yes
No
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• Awesome!!!
• Lets see how you do on the next question.

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Sorry

• Remember that right angles often have a square
  at the vertex.

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• How about this angle? Is it a right angle?

Yes
No
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Great!!!

• You really know your right angles!

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Sorry

• Remember
• If an angle is not a square corner, it is not
  a right angle.

Lets try again.
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Lets try one more question

• Fill in the blank A right angle is _____
  degrees.

A. 90
B. 30
B. 30
B. 30
C. 120
C. 120
C. 120
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Fantastic!!!

• A right angle is always 90.

Click here and choose a new area of angles to
explore.
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Thats too bad?

• A right angle is always 90.

Lets try again.
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The Basics of Angles

• An angle is formed when two lines or two line
  segments meet at a point.
• Heres an angle formed by 2 rays
• Heres an angle formed by 2 line segments

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More Basics of Angles

• This is the symbol for an angle
• Angles are measured in degrees.
• For example, if an angle is 35 degrees, we write
  it like this

Notice the symbol for degrees.
35
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And More Basics of Angles

• All angles have a vertex.
• The vertex is like the elbow of the angle.

Im a vertex.
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How We Mark an Angle

• Sometimes we make a curve at the vertex to show
  measurement.
• When the angle is a right angle, we often draw a
  square at the vertex.

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Very Important Info!!!
Even though we share the same vertex, I measure a
different angle than that green arc over there.
I measure a different angle than that red arc
over there.
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Angles Are All Around Us
Click here to learn about the types of angles.
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Acute Angles

• An acute angle is greater than 0 and less than
  90.
• An acute angle is more closed than a right
  angle.

Right Angle Square Corner
Acute Angle
Acute Angle
Acute Angle
Acute Angle
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PacMan and the Acute Angle

• This is Pac-Man.
• Pac-Mans mouth is an acute angle.
• Acute angle
• Isnt Pac-Man cute?
• Acute

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Lets Take a Quiz!

• Can you pick the acute angle?

A.
B.
C.
D.
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Great!

• You really know your acute angles!

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Sorry

• An acute angle is between 0 and 90.
• An acute angle is more closed than a right
  angle.

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Lets Try Another Question

• True or False An acute angle is less than 90.

False
True
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Sorry, Lets Review Acute Angles

• An acute angle is greater than 0 and less than
  90.
• An acute angle is more closed than a right
  angle.

Right Angle Square Corner
Acute Angle
Acute Angle
Acute Angle
Acute Angle
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Excellent!
Youre getting good at this!
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One More Question

• Which one of these is an acute angle?

1.
2.
3.
4.
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Great!

• You really know your acute angles!

Click here to check out other types of angles.
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Sorry

• An acute angle is between 0 and 90.
• An acute angle is more closed than a right
  angle.

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Reflex Angles

• Reflex angles are between 180 and 360.
• A 180 angle is a straight line.
• A 360 angle is a completely closed angle.
• Reflex angles are in between.

180
360
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Examples of Reflex Angles
240
270
335
210
260
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Lets Check Your Reflexes!

• Which one of these is an reflex angle?

1.
340
2.
3.
30
4.
90
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Wow!!!

• Great job! Now try one more.

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Sorry, Lets Review Reflex Angles

• Reflex angles are between 180 and 360.
• A 180 angle is a straight line.
• A 360 angle is a completely closed angle.
• Reflex angles are in between.

180
360
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Examples of Reflex Angles
240
270
335
210
260
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Lets See If You Know This One

• A reflex angle is

A. Between 0 and 90.
B. Between 180 and 360.
C. Between 90 and 360.
D. Between 90 and 180.
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Sorry, Lets Review

• Reflex angles are between 180 and 360.
• A 180 angle is a straight line.
• A 360 angle is a completely closed angle.
• Reflex angles are in between.

180
360
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Examples of Reflex Angles
240
270
335
210
260
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Great Job! One More Question
The two lines below form two angles. Which angle
is the reflex angle?
The Green One!
The Orange One!
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Sorry, Lets Review

• Reflex angles are between 180 and 360.
• A 180 angle is a straight line.
• A 360 angle is a completely closed angle.
• Reflex angles are in between.

180
360
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Examples of Reflex Angles
240
270
335
210
260
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Stupendous!!!

• You really know about reflex angles ?.

Click below to return to the main menu.
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Obtuse Angles

• An obtuse angle is open more than a right angle.
• But an obtuse angle is more closed than a
  straight line.
• An obtuse angle is between 90 and 180.

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Angle Diagram
Im a right angle.

• This diagram shows the different types of angles
  from the starting point.
• Red shows acute angles.
• Green shows obtuse angles.
• Purple shows reflex angles.
• Yellow shows a right angle.

Acute
Obtuse
Starting Line
Reflex
Note An angles starting line is different every
time. We judge the angle on how many degrees it
opens up.
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More About Obtuse Angles

• Remember this diagram?
• The green area shows obtuse angles.

Im still a right angle
Acute
Obtuse
Starting Line
Reflex
Note An angles starting line is different every
time. We judge the angle on how many degrees it
opens up.
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Lets Take a Quiz!

• Can you pick the obtuse angle?

A.
B.
C.
D.
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Sorry, Lets Review Obtuse Angles

• An obtuse angle is open more than a right angle.
• But an obtuse angle is more closed than a
  straight line.
• An obtuse angle is between 90 and 180.

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Sorry ?

• This one was tricky.
• We know the angle is not obtuse for 2 reasons.
• The angle has a square at the vertex.
• The angle is a square corner.
• Both of these facts make it a right angle.

Lets try again.
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Great!
Lets try another.
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An Obtuse Question

• How many degrees are in a obtuse angle?

A. An obtuse angle is between 90 and 180 degrees.
B. An obtuse angle is between 0 and 90 degrees.
C. An obtuse angle is 90 degrees.
D. An obtuse angle is between 180 and 360 degrees.
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Sorry, Lets Review Obtuse Angles

• An obtuse angle is open more than a right angle.
• But an obtuse angle is more closed than a
  straight line.
• An obtuse angle is between 90 and 180.

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Way to Go!

• Knowing how many degrees are in an obtuse angle
  is as important as knowing what it looks like.

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A Truly Obtuse Question

• True or False This angle is obtuse.

True
False
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?

• I have some good news and some bad news.
• The Bad News If you thought this was a reflex
  angle, you were wrong.
• Pay attention to the measurement arc.
• The Good News If the measurement arc was on the
  other part of the angle, it would be a reflex
  angle.

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YES!
You still knew it was an obtuse angle even though
it was rotated. You are a clever kid!
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The Project

• Your mission is to create a collage.
• You will use a large piece of paper.
• Divide the paper into 4 sections like this

Right
Acute
Obtuse
Reflex

• Label the four sections like this

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Making the Angles Collage

• Cut out pictures of the 4 types of angles.
• Draw in the vertex, measurement arc, and lines
  with a magic marker, crayon or paintbrush.
• Make it beautiful.
• We will post these in the classroom for the world
  to see!

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Right
Acute
Reflex
Obtuse
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Angle Collage Checkbric

• 1. Did I write my name on the paper?
• 2. Did I divide the paper into 4 sections?
• 3. Did I label the sections Right, Acute,
  Obtuse, and Reflex?
• 4. Did I include at least 5 examples of each
  type of angle?
• 5. Did I mark all lines or line segments?
• 6. Did I draw a dot for all the vertexes?
• 7. Did I draw measurement arcs for each angle?
• 8. Did I put my own personal flavor into the
  project?
• 9. Is my project neat?
• 10. Is my project beautiful?