Objectives (5 - 7 minutes)

1. Identify the basic components of a triangle: vertices, sides, and internal angles.
2. Recognize the properties of triangles regarding the number of sides and angles and relate them to their components.
3. Differentiate triangles according to the measurement of their sides (equilateral, isosceles, and scalene) and their angles (right, acute, and obtuse).

The above objectives aim to develop students' ability to understand and differentiate the components of triangles, as well as the properties that define them. Through practical and interactive activities, students will be encouraged to explore, identify, and relate these components and properties, enhancing their logical-mathematical thinking.

Introduction (10 - 12 minutes)

1. Concept Review: The teacher starts the lesson by reminding students about flat geometric shapes, such as squares, rectangles, circles, and especially triangles. This can be done through interactive questions like "How many sides does a triangle have?", "How many angles does a triangle have?", and "What are the sides of a triangle like?"

2. Problem Situation: The teacher presents two problem situations involving triangles. The first one could be: "Imagine you are building a roof for a toy house. You will need many triangles. How will you know that the triangles you are building are equal?" The second situation could be: "You are drawing and want to make a triangle with different side lengths and angles. How can you do that?"

3. Contextualization: The teacher explains that triangles are very important in mathematics and everyday life, as they are the basis for constructing many other geometric shapes. For example, the teacher may mention that the sum of the internal angles of a triangle is always 180 degrees, a property used to measure angles in many professions, such as architecture and engineering.

4. Capturing Students' Attention: The teacher introduces the importance of the subject with two curiosities. The first one could be: "Did you know that the triangle is the only geometric shape that cannot be distorted? If you take three sticks and try to change the shape of the triangle, you will see that it is not possible." The second curiosity could be: "Did you know that triangles are used to measure distances? In ancient times, people used the shadow of a triangle to measure the height of a mountain or the distance to an island."

The teacher must ensure that students understand the importance and relevance of the subject, as well as awaken their interest and curiosity in the topic.

Development (20 - 25 minutes)

The teacher should choose one of the following practical activities so that students can explore and learn about the components of triangles. The activities are designed to be interactive and engaging, allowing students to learn in a playful and fun way.

Activity 1: Building Triangles

1. Materials Needed: Paper, pencil, ruler, scissors, glue, and toothpicks (or any material that can be used to create triangles).

2. Step by Step:

   • The teacher divides the class into groups of 3 or 4 students. Each group will receive a sheet of paper, pencil, ruler, scissors, glue, and a limited number of toothpicks.
   • The teacher then instructs the students to try to create different types of triangles (equilateral, isosceles, and scalene) using the toothpicks and glue. They should draw the triangle on the paper before gluing the toothpicks.
   • The teacher circulates around the room to help and guide the students, clarifying doubts and reinforcing important concepts.
   • After completing the activity, each group presents their triangles to the class, explaining why they classified them in that way (based on sides and angles).

Activity 2: Triangle Treasure Hunt

1. Materials Needed: Sheets of paper with triangles drawn in different ways (equilateral, isosceles, and scalene), pencils, and erasers.

2. Step by Step:

   • The teacher divides the class into groups of 3 or 4 students. Each group receives a sheet of paper with drawn triangles.
   • Through the "Treasure Hunt," students must find and classify the triangles according to the measurement of the sides and angles. They should mark the classification of each triangle on the paper and draw a small illustration of the triangle (for example, an equilateral triangle with all sides equal).
   • The teacher circulates around the room, encouraging discussion and collaboration among group members, as well as clarifying doubts and reinforcing concepts.
   • At the end of the activity, each group presents their results to the class, explaining how they classified the triangles in the "Treasure Hunt".

In both activities, the teacher must ensure a cooperative learning environment, where students have the opportunity to discuss and share their ideas, promoting a greater understanding of the components of triangles. The teacher should also take the opportunity to reinforce the importance of communication and teamwork.

Feedback (10 - 15 minutes)

1. Group Discussion (5 - 7 minutes): After completing the activities, the teacher gathers all students in a discussion circle. He asks each group to share their solutions and conclusions, explaining how they classified the triangles and why. The teacher should ask questions to stimulate participation and critical thinking, such as: "Why do you think this is an isosceles triangle?" or "How did you decide that this is a right triangle?".

   The objective of this stage is to promote students' reflection and communication about what they have learned. Additionally, it allows the teacher to identify possible difficulties in understanding and correct misconceptions, if necessary.

2. Connection to Theory (3 - 5 minutes): The teacher then revisits the theoretical concepts discussed at the beginning of the lesson and connects them to the practical activities. He reinforces the definition of triangles and their components (vertices, sides, and angles) and discusses the properties of triangles (number of sides and angles).

   For example, the teacher can take one of the triangles created by the students in the activity and ask: "How many angles does this triangle have? And how many sides?" He can then guide the students to identify the properties of the triangle and how they relate to its components.

3. Final Reflection (2 - 3 minutes): The teacher concludes the lesson by asking students to reflect for a moment on what they have learned. He asks two simple questions to guide this reflection: "What was the most challenging part of today's lesson?" and "What did you find most interesting about triangles?".

   This stage is important to consolidate learning and for students to recognize the effort they made during the lesson. Additionally, it allows the teacher to assess the effectiveness of the lesson and plan future activities based on student feedback.

Feedback is an essential part of the lesson plan, as it helps reinforce learning, correct possible misunderstandings, and evaluate the effectiveness of the lesson.

Conclusion (5 - 7 minutes)

1. Summary of Contents (2 - 3 minutes): The teacher starts the conclusion by recapping the main points covered during the lesson. He recalls the components of triangles (vertices, sides, and internal angles), the properties of triangles (number of sides and angles), and the different classifications of triangles (equilateral, isosceles, scalene, right, acute, and obtuse). The teacher can do this through interactive questions, challenging students to remember and respond.

2. Connection between Theory and Practice (1 - 2 minutes): The teacher explains how the lesson connected theory to practice. He mentions that through the practical activities, students had the opportunity to explore and manipulate the components of triangles directly, which helped solidify their theoretical understandings. Additionally, the teacher highlights that group discussion allowed students to share their ideas and learnings, enriching everyone's learning experience.

3. Extra Materials (1 minute): The teacher suggests some extra materials for students who want to deepen their knowledge on the subject. This may include children's books on geometry, educational websites with games and interactive activities about triangles, and educational videos available online. For example, the teacher can mention the website "Khan Academy" and the YouTube channel "Mundo Bita", which have quality educational resources for children.

4. Relevance of the Subject (1 minute): Finally, the teacher emphasizes the importance of the subject for daily life and other areas of knowledge. He explains that geometry, and particularly the study of triangles, is essential for understanding space and shapes around us. Additionally, the teacher mentions that many professions, such as architects, engineers, and designers, use geometric concepts in their daily work. The teacher can give concrete examples, such as the construction of houses and buildings, the design of clothes and toys, and even computer game programming.

The conclusion is an essential step to consolidate learning, reinforce the importance of the subject, and motivate students to continue exploring and learning. The teacher must ensure that students leave the lesson with a clear and confident understanding of the discussed concepts.