Transformations
Revision Notes
There are four types of transformation :1. Reflection
To describe a reflection you must state the following things :
Reflection
Mirror line (as an equation)
e.g ‘reflection, in the line x = 3’ would earn 2 marks if it was a correct description
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2. Rotation
To describe a rotation you must state the following things :
Rotation
Angle and direction (e.g. 90° clockwise)
Centre of rotation (as a coordinate)
e.g. ‘rotation, 90° anti-clockwise about (0, 0)’ would earn 3 marks if it was a correct
description
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3. Translation
To describe a translation you must state the following things :
Translation
Distance and direction (using words or vectors)
−𝟑
e.g. ‘translation, 3 left, 2 up’ or ‘translation ( )’ would earn 2 marks if it was a correct
𝟐
description
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4. Enlargement
To describe an enlargement you must state the following things :
Enlargement
Scale factor (e.g. ‘scale factor 2’ NOT ‘multiply by 2’ or ‘it doubles’)
Centre of enlargement (as a coordinate)
e.g ‘enlargement, scale factor 2, centre (1, 2)’ would earn 3 marks if it was a correct
description
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Examples
1.
Reflection in the line x = 1
2.
From R to S, rotation 90° clockwise
about (-3, 2)
3.
From A to B, translation 7 right, 3 down OR
𝟕
translation( )
−𝟑
4.
From A to B, enlargement, scale factor 3,
centre (2, 1)
Key Points
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You must only describe ONE transformation, e.g. ‘enlargement scale factor 2 and
then translated 4 right, 1 up’ would earn ZERO marks!! ‘enlargement scale factor 2’
would earn 2/3 marks
Use tracing paper to help with describing rotations
Learn basic equations of lines e.g x = 2, y = -1, y = x for describing reflections
Draw in the ray lines (example 4) to help find the centre of enlargement
You do not have to use vectors to describe translations, use words if you are not
confident with vectors
You need to be able to understand vectors for drawing translations
Exam Questions
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(3 marks)
4.
(2 marks)
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Mock Exam Questions