Geometrical Construction (Angles)







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Previous lesson:  The pupils have previous knowledge of Geometrical Construction Topic: Geometrical Construction (Angles)                        . Behavioural objectives: By the end of the lesson, the pupils should be able to 1. Definition of angles 2. Mention types of angles 3. Construction of lines and angles 4. Bisections of lines 5. Mention various types of division of lines  

Instructional Materials:

  • Wall charts
  • Pictures
  • Related Online Video
  • Flash Cards

Methods of Teaching:

  • Class Discussion
  • Group Discussion
  • Asking Questions
  • Explanation
  • Role Modelling
  • Role Delegation


Reference Materials:

  • Scheme of Work
  • Online Information
  • Textbooks
  • Workbooks
  • 9 Year Basic Education Curriculum
  • Workbooks

  Content: Topic: Geometrical Construction (Angles)            Content    

  1. Definition of Angles
  2. Types of Angles

An angle is formed when two straight lines meet at a set point. In other words, an angle is the inclination to each other of two straight lines, which meet at point as shown.


Types of Angles The unit of measurement of angles is the degree, and the instrument used to measure the value or magnitude of an angle is called a protractor.


right angle is an angle measuring 90°. Two lines or line segments that meet at a right angle are said to be perpendicular.


An acute angle is an angle measuring between 0 and 90°.


An obtuse angle is an angle measuring between 90° and 180°.


straight angle is a straight line and it measures 180°.


reflex angle is an angle measuring between 180° and 360°.


Complementary angles definition is either of two angles that added together produce an angle of 90°.


Supplementary angle is when the sum of two angles located side by side is equal to 180°.



  1. What is an angle?
  2. List 5 types of angles.
  3. What is an angle measuring between 180° and 360°
  4. What is the unit of measurement of an angle?
  5. What instrument is used for measuring angles?



Presentation: The topic is presented step by step  


Step 1: The class teacher revises the previous topics  


Step 2. He introduces the new topic  


Step 3: The class teacher allows the pupils to give their own examples and he corrects them when the needs arise.      



  1. Give two examples of softwood and their uses.
  2. Give two examples of hardwood and their uses.
  3. List 5 uses of bronze
  4. List 4 types of brass
  5. What is the definition of a point?
  6. What are the steps in bisecting a line?
  7. Mention 5 guides in making good construction.
  8. List 5 types of lines.
  9. List 5 uses of brass
  10. List 5 uses of wood
  11. List 5 uses of metals


The class teacher wraps up or concludes the lesson by giving out a short note to summarize the topic that he or she has just taught. The class teacher also goes round to make sure that the notes are well copied or well written by the pupils. He or she makes the necessary corrections when and where the needs arise.