Lesson Notes By Weeks and Term - Junior Secondary 2

Polygon

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TERM – 2ND TERM

WEEK THREE

Class: Junior Secondary School 2

Age: 13 years

Duration: 40 minutes of 5 periods each

Date:

Subject: BASIC TECHNOLOGY

Topic:  POLYGON

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

  1. Define a polygon
  2. Identify the types and sketch the types of polygons
  3. Construct regular and irregular polygon

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers,

demonstration, videos from source

INSTRUCTIONAL MATERIALS:   Videos, loud speaker, textbook, pictures, mathematical sets, drawing instruments.

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

PRESENTATION

TEACHER’S ACTIVITY

STUDENT’S

ACTIVITY

STEP 1

INTRODUCTION

The teacher describes and explain what a polygon is to the students.

Students pay

attention

STEP 2

EXPLANATION

Teacher discuss and sketch the types of polygons.

Students pay

attention and

participate

STEP 3

DEMONSTRATION

Teacher highlight the procedure to construct regular and irregular polygon

Students pay

attention and

participate

STEP 4

NOTE TAKING

The teacher writes a summarized

note on the board

The students

copy the note in

their books

 

NOTE

POLYGON

A polygon is a closed geometric figure with straight sides. It has vertices (corners) and edges connecting these vertices. Triangles, rectangles, and pentagons are examples of polygons.

Classification of polygons

Polygons can be classified based on the number of sides they have. Here are some common types:

1. Triangle: Has 3 sides

2. Quadrilateral: Has 4 sides

3. Pentagon: Has 5 sides

4. Hexagon: Has 6 sides

5. Heptagon (or Septagon): Has 7 sides

6. Octagon: Has 8 sides

7. Nonagon: Has 9 sides

8. Decagon: Has 10 sides

Regular and irregular polygon

  1. A regular polygon is a polygon with all sides of equal length and all angles of equal measure. Examples include regular triangles, squares, and hexagons.
  2. An irregular polygon, on the other hand, has sides and/or angles that are not all equal. The lengths of its sides and measures of its angles may vary. Most polygons encountered in everyday situations are irregular.

Constructing a regular octagon.

Procedure

  1. First remember, an octagon has a 8 sides.
  2. Divide the degrees in a circle 360, by the amount of sides needed.
  3. Next draw a line through the centre of the circle splitting it into two.
  4. Draw another line that is the number of degrees found in step 2 around from the line drawn in the previous step.
  5. Use this new line to repeat step 4 and continue until we have drawn lines all around the inside of the circle.
  6. Connect all of the edges of the drawn lines and then carefully erase the original circle.


EVALUATION: 1. What is a polygon?

  1. Identify and sketch the types of polygons you know
  2. Construct a regular hexagon.

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively