# Lesson Notes By Weeks and Term - Senior Secondary 1

Angles

TERM – 1ST TERM

WEEK EIGHT

Class: Senior Secondary School 1

Age: 15 years

Duration: 40 minutes of 5 periods each

Date:

Subject: Technical Drawing

Topic: ANGLES

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

I.) Define an angle.

II.) Identify and draw out the types of angles.

III.) Describe the procedure for constructing various types of angles.

IV.) Discuss the uses of angles.

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures,

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

 PRESENTATION TEACHER’S ACTIVITY STUDENT’S ACTIVITY STEP 1 INTRODUCTION The teacher explains the meaning of angles and construct each type. Students listens attentively to the teacher STEP 2 EXPLANATION Teacher discusses the uses of angles and the procedure for constructing each angle. Students exhibit attentiveness and active engagement STEP 3 NOTE TAKING The teacher writes a summarized note on the board The students copy the note in their books

NOTE

ANGLES

Angles are geometric figures formed by two rays or lines that share a common endpoint, known as the vertex. They are measured in degrees and are used to describe the amount of rotation or separation between two intersecting lines or planes.

Types of angles

Angles can be classified into several types based on their measurements and relationships with each other:

1. Acute Angle: An angle that measures less than 90 degrees.
2. Right Angle: An angle that measures exactly 90 degrees. It forms a perfect 'L' shape.
3. Obtuse Angle: An angle that measures more than 90 degrees but less than 180 degrees.
4. Straight Angle: An angle that measures exactly 180 degrees. It forms a straight line.
5. Reflex Angle: An angle that measures more than 180 degrees but less than 360 degrees.

Uses of Angles

Angles play an important role in human activities as stated by the following uses.

1.To locate the direction of places or points.

2.To give an object a desired shape or twist.

3.To carry out design tasks in computer aided design works.

4.To conduct an analysis of a system where calculations are involved.

5.For military operation such as missiles projection.

General procedure for constructing different types of angles

1. Reflex Angle (greater than 180 degrees)

- Place the protractor on one end of the line.

- Measure and mark 180 degrees on the protractor.

- Extend the line beyond the 180-degree mark to create the reflex angle.

1. Obtuse Angle (greater than 90 degrees)

- Place the protractor on one end of the line.

- Measure and mark 90 degrees on the protractor.

- Extend the line beyond the 90-degree mark to create the obtuse angle.

1. Acute Angle (less than 90 degrees)

- Place the protractor on one end of the line.

- Measure and mark less than 90 degrees on the protractor.

- Ensure the angle formed is less than 90 degrees to create the acute angle.

1. Right Angle (exactly 90 degrees)