Basic Technology JSS 2 First Term Lesson Notes Week 8

Subject: Basic Technology
Class: JSS 2
Term: First Term
Week: 8
Age: 12 years
Topic: Angles II
Sub-topic: Bisection and Construction of Angles (90°, 45°, 60°, 30°, etc.)
Duration: 40 minutes

Behavioural Objectives:

By the end of the lesson, students should be able to:

1. Understand the concept of angle bisection.
2. Construct angles of 90°, 45°, 60°, and 30°.
3. Apply these constructions in practical scenarios.

Keywords:

• Bisection: Dividing an angle into two equal parts.
• Construction: Creating angles using a compass and straightedge.
• Protractor: A tool for measuring angles.
• Vertex: The point where two lines meet.
• Ray: A line with a single endpoint extending infinitely in one direction.

Set Induction:

The teacher asks students to recall their previous lesson on angles and introduces the importance of constructing specific angles in geometry and design.

Entry Behaviour:

Students should have a basic understanding of angles and their types from previous lessons.

Learning Resources and Materials:

• Protractors
• Compasses
• Rulers
• Whiteboard and markers
• Visual aids showing angle constructions

Building Background/Connection to Prior Knowledge:

Students are familiar with measuring angles and the properties of different types of angles.

Embedded Core Skills:

• Practical skills in measurement and construction
• Problem-solving
• Critical thinking

Learning Materials:

• Angle construction charts
• Reference books on geometry and angles

Reference Books:

• Lagos State Scheme of Work
• Basic Technology for Junior Secondary Schools by NERDC

Instructional Materials:

• Protractors
• Compasses
• Graph paper

Content:

I. Bisection of Angles

1. Definition: Bisection is the process of dividing an angle into two equal parts.
2. Method:
   • Draw an angle using a protractor.
   • Use a compass to mark points on each ray.
   • Draw arcs from each marked point to intersect, creating a new ray that bisects the angle.

II. Construction of Specific Angles

1. 90° Angle:
   • Use a protractor or draw a perpendicular line using a compass and straightedge.
2. 45° Angle:
   • Construct a 90° angle and then bisect it using the method above.
3. 60° Angle:
   • Draw an equilateral triangle. Each angle is 60°.
4. 30° Angle:
   • Construct a 60° angle and bisect it to create a 30° angle.
5. Example Steps for 90° Angle Construction:
   • Draw a horizontal line.
   • Place the protractor’s midpoint at one end of the line.
   • Mark 90° and draw a ray.

15 Fill-in-the-Blank Questions:

1. Bisection of an angle means to ______ it into two equal parts.
   a) Measure
   b) Divide
   c) Extend
   d) Construct
2. A 90° angle is also known as a ______ angle.
   a) Straight
   b) Acute
   c) Right
   d) Obtuse
3. To construct a 45° angle, you first need to create a ______° angle and then bisect it.
   a) 30
   b) 60
   c) 90
   d) 120
4. A ______ is used to measure angles accurately.
   a) Ruler
   b) Protractor
   c) Compass
   d) Square
5. The point where two rays meet is called the ______.
   a) Base
   b) Line
   c) Vertex
   d) Angle
6. To draw a 60° angle, you can create an ______ triangle.
   a) Isosceles
   b) Equilateral
   c) Scalene
   d) Right
7. The angle formed by two rays is measured in ______.
   a) Meters
   b) Degrees
   c) Centimeters
   d) Liters
8. To bisect an angle, you need a ______.
   a) Ruler
   b) Compass
   c) Protractor
   d) All of the above
9. An angle of 30° is half of an angle of ______.
   a) 60°
   b) 90°
   c) 120°
   d) 150°
10. The construction of a 90° angle can be done using a ______.
    a) Ruler
    b) Protractor
    c) Compass
    d) All of the above
11. A ______ angle measures more than 90° but less than 180°.
    a) Right
    b) Acute
    c) Obtuse
    d) Straight
12. You can use a compass to find the ______ of an angle.
    a) Measure
    b) Length
    c) Bisection
    d) Width
13. A straight line represents a ______° angle.
    a) 90
    b) 180
    c) 360
    d) 270
14. The ray that divides an angle into two equal parts is called the ______.
    a) Arm
    b) Line
    c) Bisector
    d) Vertex
15. To construct angles, you need to use a straightedge and a ______.
    a) Ruler
    b) Pencil
    c) Compass
    d) All of the above

15 FAQs with Answers:

1. What is angle bisection?
   It is dividing an angle into two equal parts.
2. How do you construct a 90° angle?
   You can use a protractor or draw a perpendicular line.
3. Why is it important to construct angles accurately?
   Accurate angles are essential in geometry, construction, and design.
4. What tools do I need for angle construction?
   You need a protractor, compass, and ruler.
5. What is a 45° angle?
   It is half of a 90° angle.
6. How can I create a 60° angle?
   You can draw an equilateral triangle.
7. What does a protractor measure?
   It measures angles in degrees.
8. Can I bisect any angle?
   Yes, any angle can be bisected.
9. How do you find the vertex of an angle?
   It is the point where the two rays meet.
10. What angle is formed by a straight line?
    A straight line forms a 180° angle.
11. How do I verify my angle construction?
    You can use a protractor to measure the constructed angle.
12. What is the relationship between 30° and 60° angles?
    A 30° angle is half of a 60° angle.
13. What is the use of angle construction in real life?
    It is used in engineering, architecture, and art.
14. Can I use a compass to measure angles?
    No, a compass is used for construction, not measuring.
15. How do I practice angle construction?
    Use graph paper and practice with a compass and protractor.

Presentation Steps:

Step 1:

The teacher revises the previous topic about angles and their types.

Step 2:

The teacher introduces the new topic by explaining angle bisection and construction techniques.

Step 3:

The teacher allows pupils to contribute, demonstrating their understanding by constructing angles.

Teacher’s Activities:

• Demonstrate angle bisection and constructions.
• Guide students as they practice constructing angles.
• Discuss the applications of constructed angles.

Learners’ Activities:

• Practice constructing angles of 90°, 45°, 60°, and 30° using compasses and protractors.
• Work in pairs to compare their constructions.
• Discuss real-life applications of angles.

Assessment:

1. Define angle bisection.
2. How do you construct a 90° angle?
3. Describe the method for creating a 45° angle.
4. Explain the use of a protractor in angle construction.
5. Provide two examples of where angles are used in daily life.
6. What is the significance of the vertex in an angle?
7. How do you ensure accuracy when constructing angles?
8. What is a 60° angle used for in construction?
9. Describe how to construct a 30° angle.
10. What tools are essential for angle construction?

Conclusion:

The teacher goes around to mark the students’ work and provides feedback on their understanding of angle bisection and construction.

Explore how to bisect and construct angles accurately for JSS 2 students in Basic Technology.