Topicm0ced5afd05f11046_1528449000663_0Topic

Angles and their types

Levelm0ced5afd05f11046_1528449084556_0Level

Second

Core curriculumm0ced5afd05f11046_1528449076687_0Core curriculum

VIII. Angles. The student:

2) measures angles smaller than 180°, with the accuracy of 1°

3) draws angles smaller than 180°

4) identifies the following angles: right, acute, obtuse;

5) compares the angles;

6) identifies vertical angles and congruent angles and uses their properties.

Timingm0ced5afd05f11046_1528449068082_0Timing

45 minutes

General objectivem0ced5afd05f11046_1528449523725_0General objective

Reading, interpreting and processing data presented in different forms.

Specific objectivesm0ced5afd05f11046_1528449552113_0Specific objectives

1. Learning to identify and measure the angles.

2. Using the properties of vertical and supplementary angles.

3. Communicating in English, developing basic mathematical, computer and scientific competences, developing learning skills.

Learning outcomesm0ced5afd05f11046_1528450430307_0Learning outcomes

The student:

1. Identifies and measures the angles.

2. Is familiar with the properties of congruent and vertical angles.

Methodsm0ced5afd05f11046_1528449534267_0Methods

1. Situational analysis.

2. Discussion.

Forms of workm0ced5afd05f11046_1528449514617_0Forms of work

1. Individual work.

2. Class work.

Lesson stages

Introductionm0ced5afd05f11046_1528450127855_0Introduction

Students revise the familiar types of angles.

Task

Students draw acute and obtuse angles. They measure the values of the angles with the protractor.

Task

Students draw straight, full rotation and zero angles.

Procedurem0ced5afd05f11046_1528446435040_0Procedure

Task

Students identify each type of the following angles:

[Illustration 1]

Task

Open the applet and measuremeasuremeasure the following angles with the protractor.

[Geogebra Applet 1]

Students revise the definition of vertical anglesvertical anglesvertical angles.

Vertical anglesvertical anglesVertical angles have common vertex and the extensions of one angle’s arms are the corresponding arms of another angleangleangle.

Task

Students work individually, using the computers. Their task is the observe how the marked angles change. They check their assumptions in relation to a different pair of angles.

Students answer the following questions:

What is the relation between the vertical anglesvertical anglesvertical angles?

[Geogebra applet 2]

Students sum up the exercise

Vertical anglesvertical anglesVertical angles have the same measuremeasuremeasure.

Task

Students draw any vertical anglesvertical anglesvertical angles. Then they determine the measuremeasuremeasure of the angles drawn.

Students revise the definition of supplementary anglessupplementary anglessupplementary angles.

Supplementary anglessupplementary anglesSupplementary angles have one common arm and the other arms together create a straight line.

Task

Students work individually, using computers. Their task is to observe how the measuremeasuremeasure of the supplementary anglessupplementary anglessupplementary angles changes.

Students answer the following questions:

What is the sum of the observed supplementary anglessupplementary anglessupplementary angles?

[Geogebra applet 3]

Students sum up the exercise

The sum of supplementary anglessupplementary anglessupplementary angles is 180 degrees.

Task

Students draw any supplementary anglessupplementary anglessupplementary angles. Then they measuremeasuremeasure them and calculate their sum.

An extra task:

Students determine the angles of the following ABCD parallelogramparallelogramparallelogram.

[Illustration 2]

Lesson summarym0ced5afd05f11046_1528450119332_0Lesson summary

Students do the revision exercises. Then together they sum up the classes, by formulating the conclusions to memorise.

Supplementary angles have one common arm and the other arms together create the straight line.

The sum of supplementary angles is 180 degrees.

Vertical angles have common vertex and the extensions of one angle’s arms are the corresponding arms of another angle.

Vertical angles have the same measure.

Selected words and expressions used in the lesson plan

angleangleangle

measuremeasuremeasure

parallelogramparallelogramparallelogram

supplementary anglessupplementary anglessupplementary angles

vertical anglesvertical anglesvertical angles