How to Use a Protractor

1. How to Use a Protractor Types of Protractors

2. How to Use a Protractor --Two Major Strategies-- How to correctly place the protractor ------AND------ How to correctly read the protractor Protractor- A tool to measure angels

3. Parts of a Protractor Outer Scale Inner Scale Parts of a Protractor Zero Edge Center Mark

4. roles of a Parts Outer Scale- For measuring obtuse angles Inner Scale- for measuring acute angles Zero Edge- Center Mark- to match to ray of shape to match to vertex of shape

5. --Steps to Measuring An angle--

6. Step One: Acute or Obtuse angle? Step 1- Determine if the angle is acute or obtuse before using the protractor.

7. Step Two: Step 2- Place the center mark of the Protractor on the vertex of the angle.

8. Step Three: Step 3- Rotate the zero edge of the protractor to line up with 1 ray of the angle and for the other ray to Cross the protractor’s scale.

9. Step Four: Step 4- Read the measure of the angle of the ray that crosses the protractor’s scale (obtuse or acute value)

10. Step Four (enlarged): Is it 44o or 136o? Hint: Think about if it looks acute or obtuse. . .

11. Protractor Note Taking Guide 1. There is only one type of protractor. Circle one answer: True or False Evidence from slideshow : __________________________________ 2. According to the slide show, what is a protractor? ________________________________________________________ 3. List the Parts of a protractor. Match the parts to their roles (jobs) must match to ray of the angle numbers used for measuring acute angles must match to the vertex of the angle numbers used for measuring obtuse angles 4. List the four steps to measuring an angle: step 1: step 2: step 3: step 4:

12. 5. What is the measure of the angle in step 4 of the slide show (44o or 136o)? _________ Logically, why can’t the other choice be correct? ____________________ ______________________________________________________ 5. Does the angle measure 130 or 50 degrees? ________ Explain why the other choice is illogical? 6. Is the measure of this angle 70 or 110 degrees? _______ Explain your reasoning: _______________ __________________________________ __________________________________

13. Please complete a paper copy of the note taking guide, given to you by your Teacher, before continuing to the next slide.

15. Answer Key

16. Protractor Note Taking Guide 1. There is only one type of protractor. Circle one answer: Evidence from slideshow : __________________________________ 2. According to the slide show, what is a protractor? ________________________________________________________ 3. List the Parts of a protractor. Match the parts to their roles (jobs) must match to ray of the angle numbers used for measuring acute angles must match to the vertex of the angle numbers used for measuring obtuse angles 4. List the four steps to measuring an angle: step 1: step 2: step 3: step 4: False There are several pictures of different styles of protractors. a tool used to measure angles zero edge inner scale center mark outer scale Determine if the angle is acute or obtuse before using the protractor. Place the center mark of the protractor on the vertex of the angle. Rotate the zero edge of the protractor to line up with 1 ray of the angle and for the other ray to Cross the protractor’s scale. Read the measure of the angle of the ray that crosses the protractor’s scale (obtuse or acute value)

17. 5. What is the measure of the angle in step 4 of the slide show (44o or 136o)? _________ Logically, why can’t the other choice be correct? ____________________ ______________________________________________________ 5. Does the angle measure 130 or 50 degrees? ________ Explain why the other choice is illogical? _________________________________ _________________________________ 6. Is the measure of this angle 70 or 110 degrees? _______ Explain your reasoning: _______________ __________________________________ __________________________________ 44o The angle looks acute, not obtuse. 130o The angle looks obtuse, not acute. 110o The angle looks obtuse, not acute.

18. How to Use a Protractor Video Project Preview the following videos at web addresses: How to Read a Protractor http://www.ehow.com/video_4909008_read-protractor.html Using a Protractor: http://www.mathplayground.com/mv_using_protractor.html How to Use a Protractor to Measure Angles: http://www.youtube.com/watch?v=9IGpYOa5B04 Critique (Decide what could be improved or kept in each video): How could these videos be improved? What visual aids could you make and use to help explain how to use a protractor? Create your own video to explain how to measure angles with a protractor

19. Name: ________________________________ How to Use a Protractor Video Project Directions: -Work in a group of 2 or 3 students. Names in group: ________________________________________________ -Write a screenplay to explain how to use a protractor to measure angles -Screenplay format looks like this: Jayden: (holding protractor) Today we are going to show you how to use a protractor to measure angles. Miranda: (pointing to an angle). The first thing that you need to do is . . . -Each line of the screenplay should tell the name of the actor, have his/her actions in ( ), and the “line” that the person is going to say. -Be sure to show/explain correct ways to measure and incorrect ways. -Be sure to have visual aids (some angles drawn in dark marker so we can see them on the video, protractor, etc.). -Check for grammar. -Use iPad to video record the screenplay (video). -Be sure to talk loud enough that the audience and video recorder can hear you. -Send video to your teacher. -Have other group(s) critique your video. ____ ____ ____ ____ ____ ____ ____ ____ ____

20. Video Critique Forms Directions: Watch the video from a different group and answer these questions Names in group who made video you are watching: ____________________________________________ 1. Did the group use visual aids? (drawings, pictures, real protractor, etc.) _________ Give examples used in video:____________________ 2. Did the group explain correct ways to use the protractor? ________________ Explain what they did: ____________________________________________ 3. Did the group show incorrect ways to use the protractor? _______________ Explain what they did: ____________________________________________ 4. Did the group talk loud enough that you could hear what they were saying?______ 5. What could the group improve on next time? ____________________________________________ 6. Best thing(s) about this video: _________________ ____________________________________________ Directions: Watch the video from a different group and answer these questions Names in group who made video you are watching: ____________________________________________ 1. Did the group use visual aids? (drawings, pictures, real protractor, etc.) _________ Give examples used in video:____________________ 2. Did the group explain correct ways to use the protractor? ________________ Explain what they did: ____________________________________________ 3. Did the group show incorrect ways to use the protractor? _______________ Explain what they did: ____________________________________________ 4. Did the group talk loud enough that you could hear what they were saying?______ 5. What could the group improve on next time? ____________________________________________ 6. Best thing(s) about this video: _________________ ____________________________________________

21. Funny video: My Protractor and I Music video: http://www.youtube.com/watch?v=NIoZsFjMfCE