# Session 37: Triangles

<div align="left" dir="ltr" id="bkmrk-session-title-triang"><table style="width: 115.476%; height: 416.969px;"><colgroup><col style="width: 37.142857%;" width="199"></col><col style="width: 62.738095%;" width="434"></col></colgroup><tbody><tr style="height: 29.7969px;"><td class="align-center" style="height: 29.7969px;">**Session Title**

</td><td class="align-center" style="height: 29.7969px;">**Triangle**

</td></tr><tr style="height: 154.016px;"><td style="height: 154.016px;">Objective

</td><td style="height: 154.016px;">By the end of the lesson, students will be able to:

  
1. Identify and name triangles based on sides and angles.
2. Understand that a triangle has 3 sides and 3 angles.
3. Discover and state that the sum of the interior angles of a triangle is 180°.
4. Collaborate in groups and reflect on their learning.

</td></tr><tr style="height: 29.7969px;"><td style="height: 29.7969px;">Concept

</td><td style="height: 29.7969px;">The world of triangles

</td></tr><tr style="height: 126.969px;"><td style="height: 126.969px;">Materials Required

</td><td style="height: 126.969px;">1. Pictures of triangle, square, rectangle, circle
2. Instruments box
3. Board &amp; Chalk
4. A4 sheet &amp; Crayons
5. Work sheet

</td></tr><tr style="height: 46.5938px;"><td style="height: 46.5938px;">Methodology

</td><td style="height: 46.5938px;">Activity oriented

  
</td></tr><tr style="height: 29.7969px;"><td style="height: 29.7969px;">Session Duration

</td><td style="height: 29.7969px;"> 90 Minutes

</td></tr></tbody></table>

</div>### Introduction Activity (15 minutes) 

**Mandala Patterns**

- **Concepts**: Circles, radial symmetry, angles, pattern repetition

**How:**

- Students use compasses and protractors to make mandalas.
- Emphasizes symmetry and repeated geometric patterns.
- Can be colored for relaxing mindfulness activity too.

**Example:**(Draw the picture given below on a chart)

![](https://lh7-rt.googleusercontent.com/docsz/AD_4nXcpdbY2wJN1ijd1UqkzYT_RxATUSTuPalAvm6TOp9C1HrKBDeZJiN9E3aQ8lqiTgsYQRjKQAt9CCafamVfSdyFCpY0-gg_oTFGYyGG_oFrHLrIzEjpLPEKYrbibnIcwhd33p5IPKg?key=cRT8aGN5drCWLEYfTuvgiYl3)

### Main Activity (70 minutes)

**What’s a Triangle? Discussion (10 minutes)**

Show pictures of different shapes (triangle, square, rectangle, circle).

Ask: Which one is a triangle? How do you know?

Students share prior knowledge.

Teacher highlights:

A triangle has 3 sides and 3 angles. It’s a closed shape.

**Story Time : (15 minutes )**

In the Triangle Kingdom, every triangle has a secret code: its 3 angles must always work together to form a straight line (180°) to keep the kingdom safe!

**Characters:-**

- Prince Equi (Equilateral)
- Sir Righty (Right triangle)
- Lady Acuta (Acute triangle)
- General Obtusa (Obtuse triangle)

The sum of the interior angles of any triangle is always equal to 180 degrees.

In mathematical notation, for a triangle ABC with interior angles angle A, angle B, and angle C, the triangle sum theorem can be expressed as:

‹A + ‹ B + ‹C = 180⁰

**Ask**: Can you guess how their angles work together?

**Student Engagement:- (10 minutes )**

Ask students to act out triangle characters (e.g., stretch arms to represent different angles).

**Key Concept : ( 10 minutes )**

**Definition of a triangle**

- A closed figure with 3 sides and 3 angles.

**Types of triangles by sides**

- Equilateral (3 equal sides)
- Isosceles (2 equal sides)
- Scalene (no equal sides)

**Types of triangles by angles**

- Acute triangle (all angles &lt; 90°)
- Right triangle (one angle = 90°)
- Obtuse triangle (one angle &gt; 90°)

**Group Activity- Angle Detectives (20 minutes )**

Make students into small groups(3 or 4)

![](https://lh7-rt.googleusercontent.com/docsz/AD_4nXc60s4aku5Ew7qXv-Z0GfAXo_4iJE0XK7WZQa7kvLDaqRd1CAJvFmOYCA2_EgHRvYJdrbPemHM5HHIoGTXVgkNhQe0o7idAvr8qwODOWFNp2uu9Tbcm5C6PgI58M0x0HGKtItAO?key=cRT8aGN5drCWLEYfTuvgiYl3)

- Give each group a work sheet of triangle with one missing angle.
- Students solve for the missing angle by subtracting from 180°.

### Review Questions(5 minutes)

- What is a triangle?
- How many angles does a triangle have?

### Follow up Task (5 minutes)

- Name a real-life object or structure that uses a triangle shape. Why is it used?
- Draw a triangle where one angle is 90°. What type of triangle is it?

### Expected Learning Outcome:

**Knowledge building-**

- This focuses on conceptual understanding and facts. You help students understand what a triangle is, its types, and properties.

**Skill building-**

- Conceptual understanding
- Problem solving

**Resources**

[https://drive.google.com/file/d/1lkchm4tNLyq2JxJMW7rv2Si1XgdzZI7h/view?usp=drivesdk](https://drive.google.com/file/d/1lkchm4tNLyq2JxJMW7rv2Si1XgdzZI7h/view?usp=drivesdk)