MATHEMATICS
FORM 2
TRANSFORMATIONS -REFLECTIONS
By : Inocentia Justin
SM St. Michael, Penampang SABAH > inojay @teacher.com > Update : 19.07.2007
PROTEKMEDIA BTPN SABAH
   
  Page 1 | Page 2  

Introduction:

Pictures of reflection

 
Lesson 1:

Definition of  reflection :  A reflection is a transformation where all the points in a plane are reflected in a line called the axis of reflection

 
Lesson 2: How to determine the image of an object under a reflection using tracing paper:

Activity :

  1. Distribute tracing papers to the students.
  2. Ask students to fold the tracing paper in two, draw the folded line and label as PQ.
  3. Let them draw any picture they like on one side of the tracing paper.
  4. Ask them to exchange paper and try to trace the picture on to the other side of the tracing paper.

Note : Line PQ is called the axis of reflection

Lesson 3: Explore the properties of reflection:
  1. Using the tracing paper in Lesson 2, ask the students to label a certain points on the object and the image.
  2. Join each point to its image, example A --> A', B --> B'. Measure the distance between A and the line PQ and the distance between A' and the line PQ.  Repeat with other points. Ask the students to make a conclusion.

*** Properties of reflection :

  • The shape and size of the object and its image are the same.
  • The orientation of the image is laterally inverted as compared to that of the object.
  • The axis of reflection, line PQ is the perpendicular bisector to the line joining the object and its image.

 
   



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