## Lesson Plan for Mathematics (Junior Secondary 2)
### Topic: Angles in Polygons
#### Lesson Overview
In this lesson, students will learn about the properties of angles in various polygons. They will learn how to calculate the sum of interior angles and how to find the measure of each interior angle in regular polygons. This lesson includes a mix of direct instruction, guided practice, and individual work.
#### Objectives
By the end of this lesson, students should be able to:
1. Define and classify polygons.
2. Calculate the sum of the interior angles of any polygon.
3. Calculate the measure of each interior angle in regular polygons.
4. Apply these concepts to solve problems involving polygons.
#### Materials Needed
- Projector or whiteboard
- Polygon charts (triangles, quadrilaterals, pentagons, etc.)
- Rulers and protractors
- Worksheets
- Pencils, erasers, and notebooks
- A calculator (optional)
#### Lesson Duration
- Total: 60 minutes
### Introduction (10 minutes)
1. **Warm-up Activity:**
- Begin with a quick review of basic properties of polygons. Ask students to define a polygon and give examples.
- Briefly discuss different types of polygons (triangle, quadrilateral, pentagon, hexagon, etc.).
2. **Set the Stage:**
- Introduce the lesson topic and objectives. Explain that today they will learn about the angles inside polygons.
### Direct Instruction (15 minutes)
1. **Properties of Polygons:**
- Define polygons and discuss the classification based on the number of sides.
- Explain the terms "interior angles" and "exterior angles."
2. **Sum of Interior Angles:**
- Use the whiteboard/projector to show that the sum of the interior angles of a polygon can be found using the formula:
\[(n - 2) \times 180^\circ \]
where \( n \) is the number of sides.
3. **Regular Polygons:**
- Explain that in regular polygons (all sides and angles are equal), each interior angle can be found by dividing the sum of the interior angles by the number of sides:
\[\text{Each Interior Angle} = \frac{(n - 2) \times 180^\circ}{n}\]
### Guided Practice (15 minutes)
1. **Example Problems:**
- Work through a couple of examples with the class, demonstrating how to apply the formulas.
- Example 1: Find the sum of the interior angles of a pentagon (5 sides).
- Example 2: Find the measure of each interior angle in a regular hexagon (6 sides).
2. **Class Discussion:**
- Ask students for observations and questions to ensure understanding.
### Independent Practice (15 minutes)
1. **Worksheet Activity:**
- Hand out worksheets containing several problems for students to practice calculating the sum of interior angles and the measure of each interior angle in regular polygons.
- Circulate the classroom to offer individual assistance as needed.
### Conclusion (5 minutes)
1. **Review and Recap:**
- Briefly review the main points of the lesson: how to calculate the sum of interior angles and how to find the measure of each interior angle in regular polygons.
2. **Exit Ticket:**
- Have each student write down one thing they learned and one question they still have about angles in polygons.
### Assessment
- Monitor student participation during guided practice.
- Collect and review the worksheet activities for understanding.
- Evaluate the exit tickets to assess comprehension and address any remaining questions in future lessons.
### Homework Assignment
- Assign a few additional problems for homework, ensuring a mix of calculating interior angles in both regular and irregular polygons.
#### Extensions
- For advanced students, introduce the concept of exterior angles and how their sum is always 360 degrees, regardless of the polygon.
This lesson plan engages students with both theoretical and practical aspects of angles in polygons, promoting both understanding and application of mathematical concepts.