# Lesson Planning Steps

## Lesson Note on Geometry

Subject: Mathematics

Theme: Geometry (Similar Shapes)

Topic: Similarity & Enlargement

Sub Topic: Similarity

Date: dd/mm/yyyy

Class: J.S.S.3

Duration: 35 Minutes

No of Learners: 30

### Learning Objectives:

By the end of the lesson learners should be able to:#### Say what similarities mean.

#### Identify similar objects by comparing corresponding sides.

#### Identify similar objects by comparing corresponding angles.

When two or more objects or figures appear the same or equal due to their shape, this property is known as a similarity.

#### Rationale:

In this lesson, learners will explore several shapes to find out which of them are similar. Objects are similar if they are proportional in size and shape. The similarity is an aspect that is widely used in our everyday life such as in the manufacturing of biscuits of the same brand being packed in different sizes of boxes that are proportional and therefore cost differently. The similarity is also used in the construction sector.

#### Prerequisite/ Previous knowledge:

Measurements, scale drawing, ratios, conversions from one unit to another, sets.

#### Teaching/ Learning Materials:

Mathematical set, real objects, worksheets, pencils, rulers, and A4 sheet papers.

#### Reference Materials:

New General Mathematics for Junior Secondary Schools Books 3 By Pearson

### Lesson Development:

STAGE | TEACHER'S ACTIVITY | LEARNER'S ACTIVITY | LEARNING POINTS |
---|---|---|---|

INTRODUCTION full class session (5mins) | Learners are provided with several different objects. Photographs of different sizes, plastic bottles of different sizes, a mathematical set ruler, 30cm ruler, cut-outs of different shapes and soap of the same brand but in different sizes.- Observe the objects and match them accordingly.
- Why have you matched them in that form?
| Group the objects with common features- They are of the same shape
- They are of the same design.
- They perform the same function.
| Learner’s entry points. |

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STEP 1 20mins. Development and Grouping | How would you describe that objects are similar? You have two sheets of A4 paper. - What do you notice about the two sheets of A4 paper provided? A)
| Students respond to the teacher's question.- Same shape.
- The lengths of both sheets of A4 paper are equal.
- The widths of both sheets of A4 paper are equal.
- The angles of both sheets of paper are 90 degrees and corresponding to each other.
| Developing the ideal of the concept similarity |

Fold one A4 sheet of paper equally once along the length. B) - What do you notice about the two sheets of paper?
- What can you say about the sides’ length and widths of both sheets of paper?
| - The folded sheet is half the A4 sheet of paper.
- The width of the folded sheet and that of the A4 sheet of paper is equal.
- The length of the A4 sheet of paper is twice the length of the folded sheet of paper.
- The lengths are in a ratio of 1: 2, while the widths are in the ratio of 1:1
- The lengths are in the ratio of 1:1 while the widths are in the ratio of 1:2
- The angles are all equal to 90 degrees and are corresponding to each other.
| Improving their level of understanding on similarity. | |

Fold the folded sheet along the width. C) Look at the shapes and discuss with your neighbour what you observe about them. | - The ratio of the corresponding lengths is 1:2
- The ratio of the corresponding width is 1:2
- The angles in all the sheets of paper are 90 degrees and therefore corresponding.
- A and B, B and C are not similar, because the ratios of the corresponding sides are not the same although their angles are equal to 90 degrees.
- A and A, A and C are similar because the ratios of the corresponding sides are equal and their corresponding angles are equal to 90 degrees.
| Identify similar objects by comparing corresponding sides and angles. | |

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EVALUATION 5mins | The teacher asks the students questions.- Identify which of the following figures are similar to each other. Give reasons for your choice.
| - A and D are similar because the ratios of the corresponding sides are equal and their corresponding angles are equal to 90 degrees.
- C and J are similar because of the ratios of the corresponding sides.
- E, I and F are similar because the ratios of the corresponding sides are equal and their corresponding angles are equal to 90 degrees.
- G and K are similar because the ratios of the corresponding sides are equal and their corresponding angles are equal to 90 degrees.
- H and L are similar because the ratios of the corresponding sides are equal and their corresponding angles are equal to 90 degrees.
| Asking the learners questions to assess the achievement of the set objectives. |

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CONCLUSION 5mins | How would you describe similar objects? | Objects are similar if; Their corresponding sides are in the same ratio. Their corresponding angles are equal. | Improving their level of understanding on Similarity. |