📘 Three Dimensional Shapes - Page 7 Explanation
📖 Open your textbook page number 7.
This page explains how to identify shapes around us and also shows the
difference between Prism and Pyramid.
📝 Complete the Table
“Complete the table by writing the names of the shapes that appear in the surrounding area.”
In this activity, the textbook shows some objects from our surroundings. We have to identify which three-dimensional shape each object looks like.
| Object shown | Shape name | Easy reason |
|---|---|---|
| Temple top | Cone | It has a circular base and pointed top. |
| Drum / Dustbin-like object | Cylinder | It has circular faces and a curved surface. |
| Football | Sphere | It is round like a ball. |
| Tree | Cone | Its overall shape looks pointed at the top and wide at the bottom. |
| Book | Cuboid | It has rectangular faces like a box. |
📊 Difference between Prism and Pyramid
Now the page gives a comparison table between a Prism and a Pyramid. This table helps us understand how both shapes are different.
| Prism | Pyramid | |
|---|---|---|
| Faces |
“The bottom face and the top face are triangular, squares shapes or polygonal.” “Vertical faces are rectangular.” ✅ In a prism, the top and bottom faces are equal and parallel. The side faces are rectangles. |
“The bottom face is triangular, square shape or polygonal.” “The vertical faces are triangular.” ✅ In a pyramid, there is only one bottom face. The side faces are triangles and meet at the top. |
| Vertices |
“They are on the bottom and top surfaces.” ✅ In a prism, vertices are found on both the top and bottom faces. |
“One vertex at the top and other vertices at the bottom.” ✅ In a pyramid, there is one top vertex. The remaining vertices are on the bottom face. |
| Edges |
“Three times the number of sides of top (or bottom) surface.” ✅ Example: If the bottom face has 5 sides, then a prism has 5 × 3 = 15 edges. |
“Twice the number of sides of the bottom surface.” ✅ Example: If the bottom face has 5 sides, then a pyramid has 5 × 2 = 10 edges. |
| Diagram |
📦 Prism It has top and bottom faces. |
🔺 Pyramid It has one top vertex. |
A prism has two equal faces: one at the bottom and one at the top. A pyramid has one bottom face and one top point.
🤔 Think About
2) “In which shape are all the faces triangular in shape?”
3) “If we keep on increasing the number of sides of base polygon then which 3D shape will be formed ?”
✅ Answer 1
A cube is a prism. It has a top face and a bottom face of the same shape. Its vertical faces are also square.
✅ Answer 2
A triangular pyramid has all faces triangular in shape.
✅ Answer 3
If we keep increasing the number of sides of the base polygon, the base starts looking like a circle.
So, in case of a prism, it forms a cylinder. In case of a pyramid, it forms a cone.
Many-sided prism → Cylinder
Many-sided pyramid → Cone
🌟 Page Summary
- 📌 We identified shapes from surrounding objects.
- 📦 A prism has top and bottom faces of the same shape.
- 🔺 A pyramid has one bottom face and one top vertex.
- 📐 In a prism, vertical faces are rectangular.
- 🔺 In a pyramid, vertical faces are triangular.
- 🟦 A cube is a prism.
- ⚪ A many-sided prism looks like a cylinder.
- 🔺 A many-sided pyramid looks like a cone.
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