Mathematics - Junior Secondary 3 - Construction of angles

TERM: 3^RD TERM

WEEK 2

Class: Junior Secondary School 3
Age: 14 years
Duration: 40 minutes of 5 periods
Subject: Mathematics
Topic: Construction of Angles
Focus: Copying Given Angles and Construction of Simple Plane Shapes
SPECIFIC OBJECTIVES:
By the end of the lesson, pupils should be able to:

1. Accurately copy a given angle.
2. Construct simple plane shapes (such as triangles, squares, and rectangles).
3. Use geometric tools like rulers, protractors, and compasses to create accurate shapes.
4. Identify and name the parts of constructed plane shapes.
5. Apply knowledge of plane shapes in solving geometric problems.

INSTRUCTIONAL TECHNIQUES:
• Question and answer
• Guided demonstration
• Practical exercises
• Problem-solving activities

INSTRUCTIONAL MATERIALS:
• Rulers
• Protractors
• Compasses
• Worksheets
• Whiteboard and marker

PERIOD 1 & 2: Copying Given Angles

PRESENTATION:

NOTE ON BOARD:
• Step 1: Draw the baseline.
• Step 2: Place the protractor at the vertex.
• Step 3: Transfer the angle measurement to the new vertex and draw the second arm.

EVALUATION (5 exercises):

1. Copy the given angle of 30° on your sheet.
2. How do you ensure the angle is copied accurately?
3. What tools do you need to copy an angle?
4. What is the importance of accurate angle copying in construction?
5. What is the angle formed when two lines intersect at 30°?

CLASSWORK (5 questions):

1. Copy an angle of 45° given on the board.
2. Label the vertex and arms of your copied angle.
3. Identify any real-life examples where angles are copied.
4. Copy a 60° angle and compare it with a classmate’s.
5. Write down the steps for copying an angle.

ASSIGNMENT (5 tasks):

1. Copy an angle of 30° from a given diagram.
2. What is the value of the adjacent angle if the angle copied is 30°?
3. Write the steps involved in copying a given angle.
4. Identify two situations in real life where copying an angle is needed.
5. Practice copying a 45° and 30° angle on your own.

PERIOD 3 & 4: Construction of Simple Plane Shapes

PRESENTATION:

and rectangle. | Pupils observe the teacher’s demonstration. |
| Step 3 - Demonstration | Shows how to use a ruler and protractor to construct a triangle. | Pupils follow along as the teacher constructs the shapes. |
| Step 4 - Practice | Pupils construct their own plane shapes based on given instructions. | Pupils construct a triangle, square, and rectangle. |

NOTE ON BOARD:
• Triangle: A shape with three sides and angles.
• Square: A shape with four equal sides and four right angles.
• Rectangle: A shape with four sides and four right angles.

EVALUATION (5 exercises):

1. Construct a triangle with three equal sides.
2. Draw a rectangle and label its sides.
3. How do you construct a perfect square?
4. What is the difference between a square and a rectangle?
5. Measure the angles of the triangle and record them.

CLASSWORK (5 questions):

1. Construct a square and label its sides.
2. Draw a triangle with one angle of 60°.
3. Identify the properties of a rectangle.
4. Construct a right-angled triangle.
5. Compare your shapes with those of your classmates.

ASSIGNMENT (5 tasks):

1. Construct a rectangle with sides of 6cm and 4cm.
2. Construct an equilateral triangle.
3. Draw a right-angled triangle with one side of 8cm.
4. Label the angles of your rectangle.

Write the differences between a square and a rectangle.