📘 Three-Dimensional Shapes - Page 1 Explanation
📖 Open your textbook page number 1.
The lesson begins with the title “Three-Dimensional Shapes”.
This page first gives a revision activity and then explains the meaning of dimensions.
🔁 Revision
Here, we have to look at the given objects and decide whether they are two-dimensional shapes or three-dimensional shapes.
📏 2D and 3D Shapes
🔹 A two-dimensional shape is flat. It has only length and width.
🔸 A three-dimensional shape is solid. It has length, width, and height.
🧩 Objects Given on the Page
- 🥁 Drum
- 🟩 Surface of a table
- 🎺 Reed pipe / Mouthpiece
- 🎯 Carrom-board surface
- 🎹 Harmonium
- 🛣️ Road
- 🏟️ Playground
- 🌀 Spinning Top
✅ Classification Table
| Sr. No. | 📄 Two-dimensional shape | 🧊 Three-dimensional shape |
|---|---|---|
| 1 | 🟩 Surface of a table | 🥁 Drum |
| 2 | 🎯 Carrom-board surface | 🎺 Reed pipe / Mouthpiece |
| 3 | 🛣️ Road | 🎹 Harmonium |
| 4 | 🏟️ Playground | 🌀 Spinning Top |
The words “Surface of a table” and “Carrom-board surface” are important. Here, we are talking only about the flat surface, not the full object.
✍️ Some Other Shapes
| 📄 Two-dimensional shapes | 🧊 Three-dimensional shapes |
|---|---|
| ⚪ Circle | 🧊 Cube |
| ◼️ Square | 📦 Cuboid |
| ▭ Rectangle | ⚽ Sphere |
| 🔺 Triangle | 🥫 Cylinder |
📐 Dimensions
A dimension tells us how a shape is measured. On this page, the book explains One Dimensional Shape (1D) and Two Dimensional Shape (2D).
📏 One Dimensional Shape (1D)
➖ Length
A one-dimensional shape has only one measurement. That measurement is called length.
So, a line is an example of a one-dimensional shape because it has only length.
📐 Two Dimensional Shape (2D)
📄 “Two-dimensional shapes occupy space on a flat surface.”
This means two-dimensional shapes are flat shapes. They are seen on a flat surface.
A 2D shape has two measurements:
- ↔️ Length
- ↕️ Width
In the rectangle shown on the page, the horizontal side shows Length and the vertical side shows Width.
➖ 1D shape has only length.
📄 2D shape has length and width.
🧊 3D shape has length, width, and height.
🌟 Conclusion
On page number 1, we learned how to classify objects as two-dimensional and three-dimensional shapes. We also learned about dimensions, 1D shapes, and 2D shapes.
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