How to Find Faces, Edges, and Vertices of 3D Shapes?
The concept of faces, edges and vertices plays a key role in mathematics and is widely applicable in geometry, exams, and real-world problem solving. Understanding these basic properties helps students confidently identify, count, and solve questions on 3D shapes in both classrooms and competitive exams.
What Is Faces, Edges and Vertices?
Faces, edges and vertices are the three main features of 3D (three-dimensional) shapes in maths. A face is a flat or curved surface. An edge is the line where two faces meet. A vertex (plural: vertices) is a sharp corner where two or more edges meet. You’ll find this concept used in geometry, solid shapes, and topics like surface area and volume.
Key Formula for Faces, Edges and Vertices
Here’s the standard formula for polyhedra, known as Euler’s Formula: \( F + V - E = 2 \), where F = number of faces, V = number of vertices, and E = number of edges.
Types of 3D Shapes & Their Faces, Edges, and Vertices
Several common 3D shapes appear in maths and everyday life. Each has its fixed count of faces, edges, and vertices. Recognizing these helps in quick recall for exams and practical usage.
| Shape | Faces | Edges | Vertices |
|---|---|---|---|
| Cube | 6 | 12 | 8 |
| Cuboid | 6 | 12 | 8 |
| Triangular Prism | 5 | 9 | 6 |
| Square Pyramid | 5 | 8 | 5 |
| Cylinder | 3 | 2 | 0 |
| Cone | 2 | 1 | 1 |
| Sphere | 1 | 0 | 0 |
Step-by-Step Illustration
Let’s see how to identify faces, edges and vertices using a cube as an example:
- Identify the faces: Count all the flat surfaces on the cube. A cube has 6 faces (each one a square).
- Count the edges: Look for all the lines where two faces meet. A cube has 12 edges.
- Locate the vertices: Find the corners where edges meet. A cube has 8 vertices.
Verification with Euler’s Formula:
- Identify values (Cube): F = 6, V = 8, E = 12.
- Use the formula: \( F + V - E = 2 \) → 6 + 8 - 12 = 2Formula confirmed!
Common Confusions: Curved Surfaces, Cylinders & Cones
- Cylinders have 2 flat faces (circles) and 1 curved face (the side). They have 2 edges (where the side meets the circles) but 0 vertices.
- Cones have 1 flat face (base), 1 curved face (side), 1 edge (circle boundary), and 1 vertex (the tip).
- Spheres have 1 curved face, no edges, and no vertices.
- Note: Euler's formula does not work for shapes with curved faces (like a sphere, cylinder, or cone)—only for polyhedra (flat surfaces and straight edges).
Speed Trick or Vedic Shortcut
Here’s a simple shortcut to remember the properties of some common 3D shapes:
- Cube/Cuboid: Always 6 faces, 12 edges, and 8 vertices.
- Cylinder: No corners, always 2 edges, and 0 vertices.
- Pyramid: Number of triangle faces = number of vertices at the base; add 1 face for the base.
School students preparing for CBSE or Olympiads can use quick tables or “real-life shape spotting” (like comparing a can, dice, or ice-cream cone) to remember these counts much faster. Vedantu tutors often use flashcards and online quizzes in live classes to reinforce these shortcuts.
Try These Yourself
- How many faces, edges, and vertices does a triangular prism have?
- Does a cone have any edges?
- List the faces, edges, and vertices in a cuboid found in your house (like a brick or box).
- Identify a real object that looks like a cylinder and write its properties.
Frequent Errors and Misunderstandings
- Counting curved surfaces as “edges” for cylinders and cones—remember, only where flat and curved faces meet can be called an edge.
- Forgetting that spheres have no edges or vertices at all (the surface is fully curved).
- Trying to use Euler’s formula on non-polyhedral shapes (cylinders, cones, spheres)—won’t work!
- Mixing up the difference between “face” (surface) and “side” (may be used for 2D shapes).
Relation to Other Concepts
The idea of faces, edges and vertices closely connects with surface area, volume, solid nets, and even advanced topics like topology and computer graphics. Mastering these basics makes it easier to handle surface-area and volume calculations and helps in solving geometry questions in higher classes.
Faces, Edges and Vertices in Real Life
- Dice: Cube—6 faces, 12 edges, 8 vertices
- Ice-cream cone: Cone—2 faces (1 flat, 1 curved), 1 edge, 1 vertex
- Soda can: Cylinder—3 faces (2 flat, 1 curved), 2 edges, 0 vertices
- Football: Sphere—1 face, 0 edges, 0 vertices
- Box: Cuboid—6 faces, 12 edges, 8 vertices
Quick Reference Table: Major 3D Shapes
| Solid Name | Vertices | Faces | Edges |
|---|---|---|---|
| Cube | 8 | 6 | 12 |
| Cuboid | 8 | 6 | 12 |
| Triangular Prism | 6 | 5 | 9 |
| Rectangular Pyramid | 5 | 5 | 8 |
| Cylinder | 0 | 3 | 2 |
| Cone | 1 | 2 | 1 |
| Sphere | 0 | 1 | 0 |
Classroom Tip
A fun way to remember faces, edges and vertices is:“Faces are flat or curved; edges are where faces meet; vertices are pointy corners.” Build models with clay, straws, and paper. Vedantu’s live sessions use interactive nets and real-life objects for practice and revision. Download summary charts and worksheets for extra practice.
Exam Practice and Worksheet
Practice is the key! Use CBSE and ICSE exam sample questions, solve MCQs based on faces, edges and vertices, and try fill-in-the-blanks exercises.
Sample Problem:
1. A square pyramid has how many faces, edges, and vertices?2. Count the vertices of a hexagonal prism.
3. Quick: Does a sphere have any edges?
We explored faces, edges and vertices—from definition, formula, examples, mistakes, and connections to other subjects. Continue practicing with Vedantu to become confident in solving problems using this concept.
Suggested Internal Links
- Euler's Formula – Explains how faces, edges, and vertices are connected
- Cube – Full cube breakdown and its properties
- Solid Geometry – Learn about 3D shapes and broader geometry concepts
FAQs on Faces, Edges and Vertices in Maths – Definitions, Easy Tricks & Examples
1. What are face edge and vertices?
In geometry, faces, edges, and vertices are key terms used to describe the features of three-dimensional (3D) shapes.
- A face is a flat or curved surface on a 3D shape. For example, a cube has six square faces.
- An edge is the line segment where two faces meet. For instance, a cube has twelve edges.
- A vertex (plural: vertices) is a point where three or more edges meet. A cube, for example, has eight vertices.
2. How do you identify faces, edges, and vertices?
To identify faces, edges, and vertices in a 3D shape:
- Count all the distinct flat or curved surfaces to get the number of faces.
- Trace along the lines where two faces join to find the edges.
- Locate the corners where the edges meet, as these are the vertices of the shape.
3. How to remember faces, edges, and vertices?
A simple way to memorize faces, edges, and vertices is through fun examples and hands-on activities:
- Face: Think of it as the flat surface you can place your hand on.
- Edge: Imagine the edge as the line where two surfaces meet, like the edge of a box.
- Vertex: It’s just like the corner point of a box or dice.
4. What is the formula for faces edges and vertices?
The most common relationship connecting faces ($F$), vertices ($V$), and edges ($E$) for simple polyhedra (solid shapes) is Euler's formula:
$$ F + V - E = 2 $$
For example, a cube has 6 faces, 8 vertices, and 12 edges. Applying the formula:
$6 + 8 - 12 = 2$
Vedantu’s tutors explain and demonstrate Euler’s formula using real-world objects and digital simulations, building a deep understanding of 3D figures in students.
5. What is the difference between faces, edges, and vertices in 2D and 3D shapes?
2D shapes only have edges (called sides) and vertices (corners), but they do not have faces as 3D shapes do. In contrast, 3D shapes have faces (flat surfaces), edges (where faces meet), and vertices (corners). For example, a square (2D) has 4 edges and 4 vertices, while a cube (3D) has 6 faces, 12 edges, and 8 vertices. At Vedantu, visual comparisons between 2D and 3D figures help clarify this distinction for students.
6. Which 3D shapes have the same number of faces, edges, and vertices?
Most common 3D shapes do not have the same number of faces, edges, and vertices. However, some polyhedra like the tetrahedron (triangular pyramid) have 4 faces, 6 edges, and 4 vertices. The cube, for example, has 6 faces, 12 edges, and 8 vertices. Vedantu’s instructors guide students to explore and compare different solid figures through interactive activities, emphasizing such unique properties in geometry.
7. How do faces, edges, and vertices relate to geometric nets?
A geometric net is a two-dimensional pattern that can be folded to form a 3D shape. The number of faces in the net matches the number of faces on the 3D figure, edges on the net become the edges of the solid, and where edges meet, you get vertices. Vedantu’s curriculum includes building and exploring nets to help students visualize and count the faces, edges, and vertices, strengthening spatial reasoning and geometric understanding.
8. How does Euler's formula work for different polyhedra?
Euler's formula, $F + V - E = 2$, applies mainly to convex polyhedra. For example:
- A cube: $6 + 8 - 12 = 2$
- A tetrahedron: $4 + 4 - 6 = 2$
- An octahedron: $8 + 6 - 12 = 2$
9. Why is learning about faces, edges, and vertices important in real life?
Understanding faces, edges, and vertices is crucial for solving problems in construction, design, architecture, and many practical fields. Recognizing these features helps students with spatial reasoning and understanding how objects fit together. Vedantu’s real-life examples and project-based learning make abstract geometric ideas practical and relatable for students at every academic level.
