Last Updated on May 9, 2020 by Alabi M. S.
THEME: Mensuration and Geometry
TOPIC: Measurement of Angles
By the end of the lesson, the pupils should have attained the following objectives (cognitive, affective and psychomotor):
- Measure angles in degrees using clock;
- Measure angles in degrees using protractor;
- Measure angles in a plane.
The pupils are required to already have taught and learned measurement of angle
The teacher will teach the lesson with the aid of Instructional Mathematical Set, and protractor.
METHOD OF TEACHING:
MAIN REFERENCE MATERIALS
Prime Mathematics book 6 (PMB 273); 2. New Method Mathematics book 6 (NMM 205).
CONTENT OF THE LESSON/LESSON NOTE
INTRODUCTION – 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.
1. ANGLE 90°
2. ANGLE 72°
3. ANGLE 127°
4. 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
1. An acute angle is less than 90°
2. A right angle Is 90°
3. An obtuse angle is more than 90° but less than 180°
4. A reflex angle is more than 180° but less than 360°
NOTE: Angle on a straight line is 180° and Angle at a point is 360°
MEASUREMENT OF ANGLE
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.
To deliver the lesson, the teacher adopts the following steps:
- To introduce the lesson, the teacher revises the previous lesson- time. Based on this, he/she asks the pupils some questions;
- Guides pupils in the correct placement of protractors to measure a given angle in degree;
- Pupils Activities – Use protractor and ruler to measure correctly the given angle.
- Guides pupils to indicate the edges, vertices and faces of given three dimensional shapes;
- Pupils Activities – Identify the number of edges, vertices and faces for different shapes.
- Guides pupils to measure the size of angle, indicate lines that are parallel and perpendicular in each of the given shapes;
- 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.
- To conclude the lesson for the week, the teacher revises the entire lesson and links it to the following week’s lesson (polygon).
Great Is Thy Faithfulness…