Objectives (5 - 10 minutes)

1. Understand the concept of an angle: Students should be able to understand and define what an angle is. They should know the elements that compose it (two rays and a vertex) and how angles are measured (in degrees).

2. Identify types of angles: Students should be able to identify and differentiate between the different types of angles: acute, right, obtuse, and straight. They should understand the characteristics that distinguish each type and be able to identify them in different contexts.

3. Measure angles with a protractor: Students should be able to use a protractor to measure angles. They should understand how the protractor works and how to use it correctly to measure angles in different situations.

   Secondary objectives:

   • Apply knowledge in practical situations: Students should be able to apply what they have learned about angles and angle measurement in practical situations, such as problem-solving and interpreting geometric figures.

   • Develop critical thinking and problem-solving skills: Throughout the lesson, students will be encouraged to think critically and solve problems related to the topic. This will help develop their logical and analytical thinking skills.

Introduction (10 - 15 minutes)

1. Review of previous content: The teacher should start the lesson by briefly reviewing the geometry concepts that are fundamental to understanding angles. This includes reviewing what straight lines, rays, vertices, and polygons are. This review can be done interactively, with students being asked to provide definitions and examples. (3-5 minutes)

2. Problem situation 1 - "The clock in the classroom": The teacher should then present the first problem situation to the students: "The clock in the classroom has two hands, one short and one long. Where will the hands be if the clock shows 3:15?" The teacher can draw a circle on the board to represent the clock and the hands, emphasizing that the position of the hands will form an angle. (2-3 minutes)

3. Contextualization: The teacher should explain that measuring angles is not only a mathematical skill but is also used in many everyday situations, such as navigation, engineering, architecture, and even art. (1-2 minutes)

4. Presentation of the topic: The teacher should then introduce the topic of the lesson - "Angle Measurement" - and explain that by the end of the lesson, students will be able to measure angles using a special instrument called a protractor. The teacher can show a real protractor or an image of it on the board to familiarize students with the instrument. (1-2 minutes)

5. Curiosity - "Where do we find angles in everyday life?": To spark students' interest, the teacher can propose a discussion about where we find angles in our daily lives. This may include examples such as the opening of a door, the slope of a ramp, the position of the hands on a clock, among others. The teacher can then ask students to identify more examples and write them down in their notebooks. (2-3 minutes)

Development (20 - 25 minutes)

1. Activity 1 - "The school clock" (8 - 10 minutes)

   • Description: Students will be divided into groups of 4 to 5 people. Each group will receive a large sheet of paper, a protractor, and a marker. The task will be to draw a large clock on the paper and position the hands according to the time provided by the teacher. The goal is for students to practice measuring angles in a practical and playful context.
   • Step by step:
     1. The teacher will provide each group with the time to position the hands on the clock.
     2. Using the protractor, students will measure the angle between the number 12 and each of the hands.
     3. After measuring, they will draw the angle on the clock.
     4. Students will compare the angle measurements obtained by each group member to verify the accuracy of the measurements.
   • Teacher's tip: The teacher should circulate around the room, observe the groups' work, and provide guidance as needed. It is important for students to understand that the two hands of the clock always form an angle, and that this angle changes as time passes.

2. Activity 2 - "Discovering angles" (8 - 10 minutes)

   • Description: In this activity, students will again be divided into groups. Each group will receive a box with various everyday objects, such as pencils, rulers, books, etc. Students will have to find and identify different angles in the objects in the box. They will measure the angles using the protractor and classify each angle as acute, right, obtuse, or straight.
   • Step by step:
     1. In their groups, students will select an object from the box and try to identify the angles present in it.
     2. After identifying an angle, they will measure the angle using the protractor and record the measurement.
     3. Then, they will classify the angle as acute, right, obtuse, or straight.
     4. Students will repeat this process with other objects from the box until they have identified and measured several angles.
   • Teacher's tip: The teacher should encourage students to be creative and think outside the box when identifying angles in objects. Additionally, the teacher should take advantage of this activity to reinforce the concept of different types of angles and the importance of precise measurement.

3. Activity 3 - "Mysterious angle challenge" (4 - 5 minutes)

   • Description: To conclude the Development part of the lesson, the teacher will propose a challenge to the students. The teacher will display on the board a figure that contains several angles. Students, individually, must measure the angles using the protractor and record the measurements on a piece of paper. The challenge is that one of the angles will be a "mysterious angle" that will not be discussed in the lesson. Students must try to identify what the "mysterious angle" is and record their answer. The teacher will then reveal what the "mysterious angle" is, and students will check if their measurements were accurate.
   • Step by step:
     1. The teacher will display the figure with several angles on the board.
     2. Students, individually, will measure the angles using the protractor and record the measurements on a piece of paper.
     3. Students will try to identify what the "mysterious angle" is and record their answer.
     4. The teacher will reveal what the "mysterious angle" is, and students will check if their measurements were accurate.
   • Teacher's tip: The teacher should ensure that the figure displayed on the board contains a variety of angles, including acute, right, obtuse, and straight angles, so that students have the opportunity to apply and consolidate what they have learned in the lesson.

Return (10 - 15 minutes)

1. Group discussion (5 - 7 minutes):

   • Description: The teacher should gather all students and start a group discussion. Each group will have up to 3 minutes to share their solutions or conclusions from the activities carried out. During the presentation, students should explain how they used the protractor to measure the angles and how they identified the different types of angles. Other students can ask questions or make comments after each presentation.
   • Step by step:
     1. The teacher will call each group to present their solutions or conclusions.
     2. The presenting group will have up to 3 minutes to share, explaining how they used the protractor and how they identified the angles.
     3. Other students can ask questions or make comments after each presentation.
     4. The teacher should ensure that all groups have the opportunity to present and that the discussion remains focused on the lesson topic.

2. Connection to theory (2 - 3 minutes):

   • Description: After all presentations, the teacher should give a quick review of the theoretical concepts presented at the beginning of the lesson and how they were applied during the activities. The teacher can highlight the importance of precise angle measurement and how it can be useful in different contexts.
   • Step by step:
     1. The teacher will briefly review the theoretical concepts of angles, types of angles, and angle measurement.
     2. The teacher will highlight how these concepts were applied during the activities and how precise angle measurement is important in various areas, such as engineering, architecture, art, among others.

3. Individual reflection (3 - 5 minutes):

   • Description: The teacher should propose that students reflect individually on what they learned in the lesson. The teacher will ask some guiding questions, and students will have a minute to think about their answers. The questions may include: "What was the most important concept you learned today?", "What questions have not been answered yet?", "How can you apply what you learned about angles and angle measurement in your daily life?".
   • Step by step:
     1. The teacher will propose the questions for individual reflection.
     2. Students will have a minute to think about their answers.
     3. The teacher may ask some students to share their answers with the class. This can help identify any gaps in understanding and allow the teacher to provide additional clarifications, if necessary.

4. Feedback and closure (1 - 2 minutes):

   • Description: The teacher should end the lesson by thanking the students for their participation and providing overall feedback on the class's performance. The teacher can praise the students' efforts, highlight areas where there was good progress, and provide guidance on areas that may need more practice.
   • Step by step:
     1. The teacher will thank the students for their participation and praise the class's efforts.
     2. The teacher will provide overall feedback on the class's performance, highlighting areas where there was good progress and providing guidance on areas that may need more practice.
     3. The teacher will inform the students about the topic of the next lesson and conclude the class.
   • Teacher's tip: The teacher should encourage students to continue practicing angle measurement at home. This can be done with the help of a virtual protractor, which is available for free on many math websites. Additionally, the teacher can suggest that students observe angles around them during the day as a way to apply what they have learned in real-world situations.

Conclusion (5 - 7 minutes)

1. Summary of contents (2 - 3 minutes):

   • Description: The teacher should summarize the main points covered in the lesson. They should recap the definition of an angle, the four types of angles (acute, right, obtuse, and straight), and how to measure angles using a protractor. The teacher may ask quick questions to the class to ensure that the concepts were understood.
   • Step by step:
     1. The teacher will recall the definition of an angle and the elements that compose it.
     2. The teacher will recap the four types of angles and their distinct characteristics.
     3. The teacher will review how to use a protractor to measure angles.
     4. The teacher may ask quick questions to the class to verify the students' understanding.

2. Theory-practice connection (1 - 2 minutes):

   • Description: The teacher should highlight how the lesson connected theory and practice. They can mention the practical activities carried out, such as measuring angles on the classroom clock and identifying angles in everyday objects. The teacher should reinforce that the theoretical knowledge of angles was applied in a practical and meaningful way.
   • Step by step:
     1. The teacher will recall the practical activities carried out during the lesson.
     2. The teacher will emphasize how the theory of angles was applied in these activities.
     3. The teacher may mention specific examples of how theory and practice connected.

3. Supplementary materials (1 - 2 minutes):

   • Description: The teacher should suggest additional materials for students who wish to deepen their understanding of angles. These materials may include explanatory videos, interactive games, math websites, among others. The teacher can share the links to these resources on the school's online learning platform or in a class chat group.
   • Step by step:
     1. The teacher will provide a brief description of each supplementary material.
     2. The teacher will share the links to these resources.
     3. The teacher will encourage students to explore these materials in their own time.

4. Importance of the subject (1 minute):

   • Description: To conclude the lesson, the teacher should emphasize the practical importance of knowledge about angles in everyday life. They can mention practical examples, such as the use of angles in architecture, engineering, navigation, art, among others. The teacher should encourage students to pay attention to angles in their environment as a way to apply what they have learned.
   • Step by step:
     1. The teacher will highlight the practical importance of knowledge about angles.
     2. The teacher will mention specific examples of how angles are used in different areas.
     3. The teacher will encourage students to observe angles in their daily lives as a way to apply what they have learned.
     4. The teacher will conclude the lesson by thanking the students for their participation and encouraging them to continue practicing what they have learned.