🔵Cube and Cuboid
What are Solid Shapes?
Solid shapes are three-dimensional (3D) shapes. They have length, width, and height. Unlike flat shapes (2D), you can hold them in your hand.
What is a Cube?
A cube is a solid shape with 6 square faces that are all the same size. All edges of a cube are equal in length.
Properties of a Cube:
- 6 faces (all squares)
- 12 edges (all same length)
- 8 corners (called vertices)
- Looks like a dice or a sugar cube
What is a Cuboid?
A cuboid is a solid shape with 6 rectangular faces. Opposite faces are identical.
Properties of a Cuboid:
- 6 faces (rectangles)
- 12 edges (not all equal - length, width, height)
- 8 corners (vertices)
- Looks like a shoebox or a brick
Comparing Cube and Cuboid:
| Feature | Cube | Cuboid |
|---|---|---|
| Faces | 6 squares | 6 rectangles |
| Edges | All equal | Different lengths |
| Examples | Dice, Rubik's cube | Brick, book, shoebox |
👀 See a worked example
How many faces does a cube have?
- A cube has 6 faces (all squares)
-
Answer: 6 faces **Example 2:** Is a dice a cube or a cuboid? *Solution:* - A dice has all square faces of the same size - All edges are equal - **Answer:** Cube **Example 3:** Name two real-life objects that are cuboids. *Solution:* - A brick has 6 rectangular faces - A shoebox also has 6 rectangular faces - **Answer:** Brick and shoebox
🤖 Vidi's Key Points
- Cube: 6 square faces, all edges equal
- Cuboid: 6 rectangular faces, edges can be different
- Both have 12 edges and 8 vertices (corners)
- Dice, sugar cubes → cubes
- Bricks, books, shoeboxes → cuboids
🟢Sphere and Cylinder
What is a Sphere?
A sphere is a perfectly round solid shape. Every point on its surface is the same distance from the center. It has no flat faces, no edges, and no corners.
Properties of a Sphere:
- 0 faces (no flat surfaces)
- 0 edges
- 0 vertices (corners)
- Perfectly round like a ball
What is a Cylinder?
A cylinder is a solid shape with two flat circular faces (top and bottom) and one curved surface that wraps around.
Properties of a Cylinder:
- 2 flat circular faces (top and bottom)
- 1 curved surface
- 2 edges (where the curved surface meets the circles)
- 0 vertices
- Looks like a can or a pipe
Comparing Sphere and Cylinder:
| Feature | Sphere | Cylinder |
|---|---|---|
| Flat faces | 0 | 2 circles |
| Curved surface | 1 (entire shape) | 1 (wraps around) |
| Edges | 0 | 2 |
| Corners | 0 | 0 |
| Examples | Ball, globe | Can, candle, pipe |
👀 See a worked example
How many flat faces does a sphere have?
- A sphere is completely round
- It has no flat faces at all
-
Answer: 0 **Example 2:** Name the shape of a soup can. *Solution:* - Soup can has two circular faces (top and bottom) - It has a curved surface around the side - This is a cylinder - **Answer:** Cylinder **Example 3:** How many vertices (corners) does a cylinder have? *Solution:* - A cylinder has no corners - It has 2 edges (where curved surface meets circles) - But no vertices - **Answer:** 0
🤖 Vidi's Key Points
- Sphere: perfectly round, no faces, no edges, no corners
- Cylinder: 2 circular faces, 1 curved surface, 2 edges, 0 corners
- Balls, oranges, globes → spheres
- Cans, candles, pipes → cylinders
🟣Cone and Real-Life Object Recognition
What is a Cone?
A cone is a solid shape with one flat circular face (the base) and one curved surface that comes to a point at the top (called the vertex or apex).
Properties of a Cone:
- 1 flat circular face (base)
- 1 curved surface (sloping sides)
- 1 vertex (point at the top)
- 1 edge (where the curved surface meets the base)
Comparing All Solid Shapes:
| Shape | Flat Faces | Curved Surface | Edges | Vertices |
|---|---|---|---|---|
| Cube | 6 squares | 0 | 12 | 8 |
| Cuboid | 6 rectangles | 0 | 12 | 8 |
| Sphere | 0 | 1 (whole shape) | 0 | 0 |
| Cylinder | 2 circles | 1 | 2 | 0 |
| Cone | 1 circle | 1 | 1 | 1 |
Real-Life Objects for Each Shape:
| Shape | Real-Life Examples |
|---|---|
| Cube | Dice, Rubik's cube, ice cube |
| Cuboid | Brick, book, shoebox, phone |
| Sphere | Ball, orange, globe, marble |
| Cylinder | Can, candle, pipe, battery |
| Cone | Party hat, ice cream cone, traffic cone |
👀 See a worked example
What shape is an ice cream cone?
- Ice cream cone has a circular base
- It comes to a point at the bottom
- It has 1 flat face and 1 vertex
-
Answer: Cone **Example 2:** How many vertices does a cone have? *Solution:* - A cone has one point at the top - This point is called the vertex - **Answer:** 1 vertex **Example 3:** Name a real-life object that is shaped like a cylinder. *Solution:* - A soda can has two circular faces - It has a curved surface around the side - **Answer:** Soda can (or candle, battery, etc.)
🤖 Vidi's Key Points
- Cone: 1 circular face, 1 curved surface, 1 vertex, 1 edge
- Ice cream cones, party hats, traffic cones → cones
- Spheres: no faces, no edges, no corners
- Cylinders: 2 circular faces, 0 vertices
- Cubes and cuboids have flat faces only (no curved surfaces)
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