Position and Transformation · JHS3 Mathematics

Lesson notes

Learning Objectives

Indicator: B9.3.3.1.2 - Understand enlargement and identify real-life situations involving enlargement.

By the end of the lesson, learners can:

Define enlargement as a transformation that changes the size of a shape while keeping its shape the same.
Draw the image of a given shape under an enlargement with a positive, negative, or fractional scale factor, given the centre of enlargement.
State the scale factor of an enlargement when given an object and its image.
Identify and describe at least three real-life situations that involve enlargement, such as photocopying, architectural scale drawings, and projection of images.
Describe how the properties of size and orientation of a shape change under enlargements with different scale factors.

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Curriculum details

Strand: Geometry and Measurement (Strand 3)
Sub-strand: Position and Transformation (3.3)
Content standard: B9.3.3.1 - Demonstrate understanding of how to perform an enlargement on a geometrical shape given a scale factor and describe the properties of the image under the transformation (i.e. congruence, similarity, etc.)
Indicator: B9.3.3.1.2 - Understand enlargement and identify real-life situations involving enlargement.
Suggested placement: Term 3, Week 6 (Week 30 of the year)
Our suggestion, laid out in curriculum order across three terms of twelve weeks. NaCCA does not fix the week, so follow your school's scheme of learning.
Curriculum reference: Mathematics, Common Core Programme (JHS1-JHS3), 2023, p. 210
Transcribed from the official NaCCA publication. Check this page against the source.

Exemplars (from the NaCCA curriculum)

E.g. 1. Draw an enlargement of shapes using a given scale factor.
i. State the single transformation that maps triangle P onto Q.
ii. State the single transformation that maps triangle P onto R.

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iii. Investigate the characteristics of enlargements under the following conditions of scale factor:
• if the scale factor (K) is negative
• if the scale factor (K) is greater than 1 or less than -1
• if the scale factor (K) is between -1 and 1 (i.e., fraction)
E.g. 2. Using an object, and its image, determine the scale factor in a transformation?