LESSON PLANNING OF USE PROTRACTOR

 

LESSON PLANNING OF USE PROTRACTOR TO CONSTRUCT ANGLES OF DIFFERENT MEASURES

Subject Mathematics

Grade 5^th

Students` Learning Outcomes

• Use protractor to construct, right angle, straight angler and reflex angles of different measures

Information for Teachers

• A protractor is a tool, typically made of transparent plastic, for measuring angles. Protractor is used to measure angles in degrees (⁰) in geometry lessons in schools. 
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• The circle outside an angle`s arms is termed as Exterior Angle.
• The exterior angle of an obtuse angle or acute angle is known as Reflex Angle.
• A Reflex Angle is one which is more than 1800 but less than 3600
  

 

• Consult text book at all steps where and when required.

Material / Resources

Writing board, chalk / marker, duster, geometry box, textbook

Introduction

• Ask students if they have seen sun rise or sun set?
  

 

• Draw a straight line on board and make half sun and ask how it looks at this time [show sample to the students].  
• Tell them to open their geometry box and see if there is something resembling that.
  

 

 

• Let them explore that the shape of protractor resembles a half sun.
• Ask them to DRAW SUNRISE by using protractor, the way you drew on the board. [Show sample]
• Let them try, later helping them to draw on the board with the help of a protractor.
• Ask them to read and find total number of degrees on this D- shaped tool.
• May be they will answer 180⁰ or something else.
• Tell them that this is also an angle called straight angle.
• Tell the students that there are 180⁰ degrees in a straight angle. Ask students if they have ever heard the phrase “does a one-eighty”. It means to do things in opposite direction.
• Let them try to join two protractors in a way to complete a whole circle and then ask then count number of degrees it has.
• Let them explore that there are 360⁰ degree in a circle.

 

Development

Activity 1

• Recall the concepts of angles which they have already studied in Grade 4
• Conduct one or two activities from previous grade if you find necessary.
• This will help to create a link.
• Make angle 4 of 180⁰by the hands of the clock; make the figure then change 4 directions.
• Encourage students to get ready for the game: Do as I do?
• Attempt following steps on board and ask students to do the same individually.
  

 

• Place the center of protractor at a point A which is point O.
• Look for the number 180⁰on protractor and mark a point on the paper next to 180⁰
• Take away the protractor and label the point C.
• Join point A and new point C by using ruler.
  

 

 

• Relate the clock hands and angles that 12 0` Clock is a Zero degree angle and 6 0` Clock is 180⁰angle. [Change the direction of Minute and Hour hand to form new angle]

 

Sum up / Conclusion

• Ask students what they have learnt during the period about the angles.
• Student will answer that angle of 180⁰ is called straight angle.
  

 

• Reflex Angle is one which is more than 180⁰ but less than 360⁰
  

 

 

• Reflex angle is larger angle, whereas its smaller angle may be acute or obtuse.

 

Assessment

• Give angles of different degrees to the students and ask them to draw them and identify its type.

i.                    45⁰

ii.                   170⁰

iii.                  90⁰

iv.                  20⁰

v.                   180⁰

vi.                  360⁰

Follow up

• Ask students to look for examples that show straight and reflex angles in their surroundings.
  

 

• Added 180⁰ in the noted angle that would be the required reflex angle, For example 45⁰+ 180⁰ = 225⁰
• Reflex angle will be 180⁰