Objectives (5 - 7 minutes)

1. Identify right and non-right angles: Students should be able to differentiate between a right angle (90 degrees) and a non-right angle (any angle that is not 90 degrees). This includes recognizing and drawing examples of each type of angle.

2. Classify right and non-right angles: Students should be able to classify a variety of angles as right or non-right. They should be able to justify their answers, explaining why they believe an angle is right or non-right.

3. Apply knowledge about right and non-right angles: Students should be able to apply their knowledge about right and non-right angles to solve math problems. This may include determining the measures of unknown angles based on their knowledge of right and non-right angles.

Introduction (10 - 12 minutes)

1. Review of previous content: The teacher should start the lesson by quickly reviewing previously learned geometry concepts, such as points, lines, rays, and line segments. This will help establish the foundation for the new content on right and non-right angles. (3 - 4 minutes)

2. Problem situation 1: "The mystery of the missing angle": The teacher presents an image of a square where one of the angles is missing. Students are challenged to discover the value of the missing angle. The teacher should guide students to think about what they know about right and non-right angles to solve the mystery. (3 - 4 minutes)

3. Contextualization 1: "Angles around us": The teacher shows students examples of right and non-right angles in everyday objects, such as the corner of a book (right angle) and the slope of a ramp (non-right angle). This helps connect the abstract concept of angles with students' reality. (2 - 3 minutes)

4. Problem situation 2: "Building the perfect rectangle": The teacher presents an image of an incomplete rectangle and challenges students to determine which angles are right and which are not. Students must then use this knowledge to complete the rectangle. (2 - 3 minutes)

5. Contextualization 2: "Angles on the playground": The teacher takes students to the playground (if possible) or shows images of a playground. They discuss the angles present in the playground equipment, such as the slide and the swing. This helps reinforce the idea that angles are all around us and are important parts of many things we see and use daily. (2 - 3 minutes)

Development (20 - 25 minutes)

In this stage, students should work in groups of 3 to 4, solving the proposed activities. The teacher should circulate around the room, guiding and assisting students as needed. The activities should be chosen according to the students' level of difficulty.

1. Activity 1: "Discovering angles" (10 - 12 minutes)

   • The teacher gives each group a sheet of paper with various geometric shapes (squares, rectangles, triangles, circles, etc.) drawn, some with right angles and others without.
   • Students must identify and color the right angles in one color and the non-right angles in another.
   • Then, they must measure and record the measurement of some angles in degrees, using a protractor.
   • After completion, groups present their findings to the class, explaining their choices and how they made the measurements.

2. Activity 2: "Building with angles" (10 - 12 minutes)

   • The teacher gives each group a set of popsicle sticks and modeling clay.
   • Students must build various figures (squares, rectangles, triangles, etc.) and then model and attach a stick to the top of each figure, forming an angle.
   • They must then classify each angle as right or non-right, based on its appearance and in comparison to the angles they identified earlier.
   • At the end, each group must present their figures and explain how they classified the angles.

3. Activity 3: "Solving problems" (10 - 12 minutes)

   • The teacher hands out a sheet of paper with some problems involving right and non-right angles to each group.
   • Students must read the problems and discuss possible solutions among themselves.
   • They must then represent the angles from the problem on paper, using the protractor to measure the angles, if necessary.
   • At the end, each group must present their solutions and how they arrived at them.

Throughout the process of solving these activities, the teacher should encourage communication and collaboration among group members, as well as argumentation and justification of their answers. This is important for the development of critical thinking and the ability to solve mathematical problems.

Additionally, these practical and playful activities allow students to manipulate angles and better understand the differences between right and non-right angles, making learning more meaningful and fun.

Feedback (10 - 12 minutes)

1. Group discussion: After completing the activities, the teacher should gather all students in a large circle for a group discussion. Each group will have the opportunity to share their discoveries, solutions, and strategies. (4 - 5 minutes)

   • The teacher should encourage students to explain how they decided whether an angle was right or non-right. They should describe the visual characteristics they observed and how they used the protractor to measure the angles, if applicable.

   • During the discussion, the teacher should ask questions to stimulate critical thinking and deepen students' understanding. For example: "Why do you think this angle is right/non-right?" or "How did you decide the measurement of this angle?"

2. Connection to theory: After discussing the activities, the teacher should revisit the theory, highlighting the key points learned during the practical activities. (3 - 4 minutes)

   • The teacher can remind students about the difference between right and non-right angles, and how they can be visually identified and measured.

   • The teacher should reinforce the importance of angles in geometry and everyday life, using relevant examples for students. For example, "Who can give me an example of a right angle we see every day?" or "Why do you think architects and engineers use angles in their work?"

3. Individual reflection: To conclude the lesson, the teacher should propose a moment of individual reflection, where students have a minute to think about what they learned in the lesson. (2 minutes)

   • The teacher can ask two simple questions to guide students' reflection. For example, "What was the most interesting thing you learned today about right and non-right angles?" and "How can you use what you learned today at home or at school?"

   • After the reflection period, the teacher can invite some students to share their answers with the class, if they feel comfortable.

Throughout the feedback, the teacher should encourage the participation of all students, ensuring that everyone has the opportunity to share their ideas and learnings. This helps reinforce learning, promote critical thinking, and build students' confidence in their mathematical abilities.

Conclusion (5 - 7 minutes)

1. Lesson Summary: The teacher should start the conclusion by recalling the most important aspects of the lesson. They should emphasize that the lesson was about angles, specifically right and non-right angles. They should reinforce the definitions of right angles (90 degrees) and non-right angles (any angle that is not 90 degrees) and how students can recognize them. (2 - 3 minutes)

2. Connection between Theory and Practice: The teacher should then explain how the lesson connected the theory of right and non-right angles with practical activities. They should highlight that by identifying and measuring angles in drawn, constructed, and problem situations, students directly applied their theoretical knowledge. (1 - 2 minutes)

3. Extra Materials: The teacher should suggest extra materials for students who want to further explore the topic. This may include online games or apps that help practice identifying and measuring angles, children's math books that address the topic of angles, or educational videos available on the internet. (1 - 2 minutes)

4. Importance of the Subject: Finally, the teacher should explain the importance of understanding right and non-right angles. They may mention that the ability to identify and measure angles is essential not only in mathematics but also in various areas such as architecture, design, engineering, and sciences. Additionally, the teacher can emphasize that geometry is a fundamental part of our world, and understanding geometric concepts like angles helps us better understand the environment around us. (1 - 2 minutes)

Throughout the conclusion, the teacher should ensure that students feel proud of their efforts and achievements in the lesson, reinforcing that they are capable of understanding and applying important mathematical concepts. They should also encourage students to continue exploring the world of mathematics outside the classroom, showing them that math can be fun and relevant to their lives.