📘 Three Dimensional Shapes - Page 4 Explanation

📖 Open your textbook page number 4.
This page explains Prism. It shows how three-dimensional shapes can be made by placing many equal two-dimensional shapes one above another.

🔷 Prism

A prism is a three-dimensional shape. It is formed when the same flat shape is placed again and again on top of each other. In this page, the book explains Triangular Prism and Cuboid or Rectangular Prism.

🔺 (1) Triangular Prism

In this activity, first we cut many triangles of the same size. Then we keep one triangle over another. When many equal triangles are placed on top of each other, a solid shape is formed.

The three-dimensional figure formed is called a triangular prism. It is called a triangular prism because its two main opposite faces are triangles.

🧩 Elements of Triangular Prism

In the diagram, the parts are shown as Triangular face, Edges, Vertical face, and Vertex.

• 🔺 Triangular face: The flat triangle-shaped surface of the prism.
• ▭ Rectangular face / Vertical face: The side flat surface of the prism. It is rectangular in shape.
• 📏 Edge: The line where two faces meet.
• 📍 Vertex: The corner point where edges meet.

So, the complete sentence is:

📦 (2) Cuboid Or Rectangular Prism

In this activity, first we cut many rectangles of the same size. Then we place the rectangles one above another. When many equal rectangles are stacked, a solid shape is formed.

The three-dimensional figure formed is a cuboid. A cuboid is also called a rectangular prism because its faces are rectangular.

🧩 Elements of Cuboid

In the diagram, the parts are shown as Top face, Vertical face, and Bottom face.

• 🔼 Top face: The upper flat surface of the cuboid.
• 🔽 Bottom face: The lower flat surface of the cuboid.
• ▭ Vertical face: The side flat surface of the cuboid.
• 📏 Edge: The line where two faces meet.
• 📍 Vertex: The corner point where edges meet.

So, the complete sentence is:

🧪 Demonstration / Practical

This means students should make different 3D shapes by using different flat shapes. For example, if square shapes are placed on top of each other, a square prism can be formed. If pentagons are stacked, a pentagonal prism can be formed. If hexagons are stacked, a hexagonal prism can be formed.

After making the shapes, students should write their names and count their vertices, faces, and edges.

⚪ Cylinder (Circular Prism)

In this activity, students cut many circles of the same radius. Then they place the circles one above another. When many equal circles are stacked, the shape formed looks like a cylinder.

Here, the cylinder is called a Circular Prism because it is made by stacking circular shapes.

👩‍🏫 Teacher Instructions

This means the name of a prism depends on the shape used to make it. If triangles are stacked, it is called a triangular prism. If rectangles are stacked, it is called a rectangular prism. If circles are stacked, it is called a circular prism or cylinder.

🌟 Conclusion

On page number 4, we learned about Prism, Triangular Prism, Cuboid or Rectangular Prism, and Cylinder or Circular Prism. We also learned that prisms can be understood by stacking equal flat shapes on top of each other.