What is a Cuboid? Meaning, Definition & Examples

The concept of cuboid plays a key role in mathematics and is widely applicable to both real-life situations and exam scenarios. Whether you’re identifying shapes in your classroom, calculating space, or preparing for maths competitions, understanding cuboids helps build your foundation in geometry.

What Is Cuboid?

A cuboid is a three-dimensional solid with six rectangular faces, twelve edges, and eight vertices. Each face of a cuboid is a rectangle, and every angle in a cuboid is a right angle (90 degrees). You’ll find this concept applied in volume calculation, mensuration, and solid geometry. In mathematics, a cuboid is sometimes called a rectangular box or a rectangular prism.

Key Formula for Cuboid

Here’s the standard formula:
Volume of a cuboid: \( V = l \times b \times h \)
Total Surface Area: \( TSA = 2(lb + bh + hl) \)
Lateral Surface Area: \( LSA = 2h(l + b) \)

Cross-Disciplinary Usage

Cuboid is not only useful in Maths but also plays an important role in Physics (calculating space and density), Computer Science (3D modeling), and daily logical reasoning. Students preparing for JEE or NEET will see its relevance in various questions, especially in geometry and real-world applications like packaging and architecture.

Step-by-Step Illustration

1. Suppose you have a cuboid box with length = 10 cm, breadth = 7 cm, and height = 5 cm.
   
   To find the volume:
   
   
2. Use the formula:
   
   Volume = length × breadth × height = 10 × 7 × 5
   
   
3. Do the multiplication:
   
   10 × 7 = 70; 70 × 5 = 350
   
   
4. Final Answer:
   
   The volume of the cuboid is 350 cm³.
   
   

Speed Trick or Vedic Shortcut

Here’s a quick shortcut for cuboid problems: If you need to find the diagonal of a cuboid, don’t calculate one face at a time. Use this shortcut:

1. Apply the formula:
   
   Diagonal = \( \sqrt{l^2 + b^2 + h^2} \)
   
   
2. Example: For a cuboid with sides 3 cm, 4 cm, 12 cm:
   
   Diagonal = \( \sqrt{3^2 + 4^2 + 12^2} = \sqrt{9 + 16 + 144} = \sqrt{169} = 13 \) cm
   
   

Shortcuts like these help you solve mensuration problems faster. Vedantu’s live sessions share more ways to boost efficiency when handling geometry questions.

Try These Yourself

• List five objects at home shaped like a cuboid.
• Find the volume of a cuboid with length 8 cm, breadth 4 cm, and height 3 cm.
• Which has more volume: a cube of side 4 cm, or a cuboid of sides 4 cm, 4 cm, and 5 cm?
• Name two differences between a cube and a cuboid.

Frequent Errors and Misunderstandings

• Mixing up cuboid and cube—remember, in a cube all sides are equal, in a cuboid they are not!
• Forgetting to use correct units (cm³ for volume, cm² for area).
• Swapping length, breadth, and height in the formulas.

Properties and Table of Cuboid

Relation to Other Concepts

The idea of cuboid connects closely with topics such as cube and rectangular prism. Mastering this helps you understand advanced geometry, surface area, and volume calculations in higher classes. For example, a cube is a special type of cuboid where all sides are equal. You can explore more differences with this comparison page.

Classroom Tip

A quick way to remember cuboid: “A cuboid has rectangle faces, while a cube has all square faces.” Teachers at Vedantu often use real boxes or books in class to let students touch and count faces, edges, and vertices. Try making your own model using matchboxes or bricks for a fun learning activity.

We explored cuboid—from definition, formula, examples, mistakes, and connections to other subjects. Continue practicing with Vedantu to become confident in solving problems using this concept. For deeper learning, check out Area of Cuboid, Volume of Cube, Cuboid and Cylinder, or Nets of Solid Shapes to understand how different 3D shapes relate.