# how to make working model to demonstrate circle theorems – maths project – tlm

Circle theorems are a set of fundamental principles in geometry that describe the relationships between angles, radii, chords, tangents, and other components of a circle.

These theorems form a crucial part of the study of Euclidean geometry and have numerous applications in fields such as engineering, architecture, and various sciences.

The working model of circle theorems provides a hands-on approach to exploring these relationships, making the abstract concepts more tangible and easier to comprehend.

Creating a working model to demonstrate circle theorems using cardboard and color paper is a great way to make these geometric concepts more tangible.

Here’s a step-by-step guide:

### Materials Needed:

1. Cardboard or foam board
2. Colored paper (different colors)
3. Compass
4. Ruler
5. Pencil
6. Scissors
7. Glue or tape
8. Protractor (optional)
9. Marker

### Steps by Step Video Instructions:

#### 1. Prepare the Base:

• Take a piece of cardboard or foam board as the base for your model.
• Cut it into a large circle to represent the circumference of a circle.

#### 2. Draw the Circumference:

• Use a compass to draw a large circle on the cardboard.
• Alternatively, you can draw a circle by tracing a round object like a plate or bowl.

#### 3. Cut Out Shapes:

• Cut out various shapes from colored paper to represent different elements of circle theorems, such as chords, radii, tangents, and secants.
• You will need shapes like triangles, rectangles, and circles (for radii).

#### 4. Label the Shapes:

• Write labels for each shape to indicate what they represent (e.g., AB for a chord, O for the center, etc.).

#### 5. Create Theorems:

• Use colored paper to represent specific theorems.
• For example, for the theorem “The perpendicular bisector of a chord passes through the center of the circle”, create a chord and a perpendicular bisector.
• For “The angle subtended by a chord at the center is twice the angle subtended at the circumference”, create a chord and measure the angles.

#### 6. Attach the Elements:

• Glue or tape the shapes representing chords, radii, tangents, and other elements onto the circle base at appropriate positions.
• Ensure the positions are accurate and clearly labeled.

#### 7. Create Tangents:

• Use colored paper to create tangent lines that just touch the circumference at a single point.
• Glue or tape these tangent lines onto the circle.

#### 8. Demonstrate Theorems:

• Use the model to demonstrate various circle theorems.
• For example, demonstrate that the angle between a tangent and a radius is 90 degrees by measuring it with a protractor.

#### 9. Label and Explain:

• Write labels and explanations for each theorem directly on the cardboard base or on separate cards.
• Include the names of the theorems and brief explanations of their meanings.