Subject : Mathematics

Class : Basic 6 / Primary  6  /Grade 6

Term : Third Term / 3rd Term

Week : Week 3

Topic : Types Of Angles

Behavioural Objectives :  At the end of the lesson, the pupils should be able to

• Explain different types of angles 
• say the properties of different types of angles 
• calculates the values of unknown values in any given angles 
• Calculate the values of unknown letters in open sentences 
• construct some of the angles that have just been taught 

Previous Knowledge : Pupils have previous knowledge of      simple open sentences          that was taught in the previous lesson

Instructional Materials :

• Pictures
• Wall Posters
• Related Online Videos
• Role Playing

Reference Materials

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

Content :

How Are Angles Formed

Angles are formed when an arm moves from an initial position to a final position . This is easily noticed when the arm of the analogue wall clock moves from an initial position to a final position , then an angle is formed . The value of an angle at a point is equal to three hundred and sixty degree. When the time on the wall clock is three o;clock , then an angle of ninety degree is formed .

An angle is also formed when two lines meet . An angle is formed at the point of interception of two lines.

Types Of Angles

Complementary Angle

Two Angles are Complementary when they add up to 90 degrees (a Right Angle).

They don’t have to be next to each other, just so long as the total is 90 degrees.

Examples:

• 60° and 30° are complementary angles.

• 5° and 85° are complementary angles.

Supplementary Angles

Two Angles are Supplementary when they add up to 180 degrees.supplementary angles 40 and 140

These two angles (140° and 40°) are Supplementary Angles, because they add up to 180°:Notice that together they make a straight angle. supplementary angles 60 and 120But the angles don’t have to be together.

These two are supplementary because60° + 120° = 180°

Acute angle:

An angle whose value is bigger than  0 degree and less than 90 degrees is said to be an acute angle . The values of acute angles may be  30°, 40°, 60° , 70° or even 89 °  .

Right angle

This is an angle whose measure or value is  equal to 90° or ninety degree .

Obtuse angle:

An angle whose value or measure is bigger than 90°  but less than 180° . Thus, it is between 90 degrees and 180 degrees.

Straight angle

This is also known as angle on a straight line An angle whose measure is 180 degrees.Thus, a straight angle look like a straight line.

Reflex angle:

An angle whose measure is bigger than 180 degrees but less than 360 degrees.

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

Evaluation :

In worksheet on angles you will solve 10 different types of questions on angles.

1. Classify the following angles into acute, obtuse, right and reflex angle:

(i) 35°

(ii) 185°

(iii) 90°

(iv) 92°

(v) 260°

2. Measure these angles:

3. Use your protractor to draw these angles:

(i) 40°

(ii) 125°

(iii) 25°

4. Identify which of the following pairs of angles are complementary or supplementary?

(i) 70°, 20°

(ii) 20°, 170°

(iii) 50°, 145°

(iv) 125°, 55°

(v) 105°, 75°

(vi) 55°, 35°

5. Find the complement of each of the following angles:

(i) 40°

(ii) 27°

(iii) 35°

6. Find the supplement of each of the following angles?

(i) 100°

(ii) 90°

(iii) 110°

(iv) 107°

7. Draw a pair of supplementary angles such that one of them measures:

(i) 120°

(ii) 90°

8. Construct the angles of the following measures with the help of a compass:

(i) 150°

(ii) 90°

(iii) 120°

9. An angle whose measure is less than 90° is called an ……………… .

10. An angle measure 0° is called a …………….. .

Assignment :

Prepare for the next lesson by reading about

POLYGON AND PLANE FIGURES