Angles

Last Updated on July 15, 2020 by Alabi M. S.


MATHEMATICS
Basic 6
TOPIC: Measurement of Angles
The corner point of an angle is called the vertex. And the two straight sides are called arms. The angle is the amount of turn between each arm.

PERFORMANCE OBJECTIVES
By the end of the lesson, the pupils should have attained the following objectives (cognitive, affective and psychomotor):
  1. Measure angles in degrees using clock;
  2. Measure angles in degrees using protractor;
  3. Measure angles in a plane.
ENTRY BEHAVIOR
The pupils are required to already learned in basic 5 and 6:
  • measurement of angle
INSTRUCTIONAL MATERIALS
The teacher will teach the lesson with the aid of:
  1. Instructional Mathematical Set
  2. protractor
METHOD OF TEACHING:

MAIN REFERENCE MATERIALS
  1. Prime Mathematics book 6
  2. New Method Mathematics book 6 
CONTENT OF THE LESSON

DEGREES AND PROTRACTOR READING
A protractor is used to measure angles. A full turn or circle is divided into 360 parts. Each part is called a degree. One degree is written as 1°. Some protractors are semi-circles as shown below.
ANGLE 90°
ANGLE 72°
ANGLE 127°
ANGLE 18°
LESSSON EVALUATION
Measure these angles  with  your protractor:

MEASUREMENT OF ANGLES

EXAMPLES 
Using a protractor, draw:
  1. Angle 75°
  2. Angle 145°
LESSON EVALUATION 
Using a protractor, draw:
  1. Angle 45
  2. Angles 66
  3. Angles 123
MEASUREMENT OF ANGLES 
TYPES OF ANGLES

An acute angle is less than 90°
A right angle Is 90°
An obtuse angle is more than 90° but less than 180°
A reflex angle is more than 180° but less than 360

NOTE:
Angle on a straight line is 180°

Angles around a point will always add up to 360°

MEASUREMENT OF ANGLE

EXAMPLE
Given < ADB is 28°
But < ADB + < ADC = 180°
28° + < ADC = 180°
< ADC = 180° – 28° = 152°
LESSON EVALUATION

Measure the angle marked x with your protractor. Calculate the angle marked y.

MEASUREMENT OF ANGLE IN A PLANE 

TRIANGLE
Measure the three angles of these triangles

Note:

Sum of angles in a triangle is 180°
Further exercise will be taken from the listed reference materials.
PRESENTATION
To deliver the lesson, the teacher adopts the following steps:
  1. To introduce the lesson, the teacher revises the previous lesson- time. Based on this, he/she asks the pupils some questions;
  2. Guides pupils in the correct placement of protractors to measure a given angle in degree;
  3. Pupils Activities – Use protractor and ruler to measure correctly the given angle.
  4. Guides pupils to indicate the edges, vertices and faces of given three dimensional shapes;
  5. Pupils Activities – Identify the number of edges, vertices and faces for different shapes.
  6. Guides pupils to measure the size of angle, indicate lines that are parallel and perpendicular in each of the given shapes;
  7. Pupils Activities – Use protractors to determine the sizes of angles in a given shape; Identify lines that are parallel and perpendicular in three dimensional shapes.
CONCLUSION
To conclude the lesson for the week, the teacher revises the entire lesson and links it to the following week’s lesson.

LESSON EVALUATION 
Pupils to:

  1. measure given angles from diagram in their textbooks, work books, etc.;
  2. draw various plane shapes and measure resulting angles to the nearest degree;
  3. identify the edges, vertices and faces of given 3-dimensional shapes;
  4. measure the sizes of angle in a two dimensional shapes. 
Great Is Thy Faithfulness…
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