Rectangular Parallelepipeds for SSC Tier-I Exam

This article provides a comprehensive guide on tackling questions on rectangular parallelepipeds in the SSC CGL Tier-I quantitative aptitude section, along with tips, formulas, practice resources and more.


The quantitative aptitude section of the SSC CGL Tier-I exam can seem intimidating for many aspirants. An important concept often tested in this section is that of the rectangular parallelepiped. Though it may seem simple at first glance, fully understanding rectangular parallelepipeds is key to solving many quantitative aptitude questions.

This article will provide a complete breakdown of the rectangular parallelepiped portion of the SSC CGL syllabus. It covers the key formulas, types of questions asked, and tips to master this concept.

Understanding Rectangular Parallelepipeds

A rectangular parallelepiped is a three-dimensional geometric figure with six rectangular faces, similar to a brick. The key aspects are:

  • Three pairs of parallel and equal faces
  • All edges meet at right angles
  • Key properties like volume, surface area, diagonal lengths can be calculated using mathematical formulas

Having a strong spatial understanding of rectangular parallelepipeds is vital for solving related questions.

Key Formulas

The main formulas pertaining to rectangular parallelepipeds include:

Formula Description
V = l x b x h Volume formula
SA = 2(lb + bh + hl) Total surface area formula
d2 = l2 + b2 + h2 Diagonal length formula

Where l, b and h are the length, breadth and height of the parallelepiped.

Types of Questions

Some common question types are:

  • Numerical questions involving direct application of volume, surface area or diagonal formulas
  • Questions involving 3D visualization to determine distances, angles or intersections
  • Multi-step word problems resulting in calculation of unknown dimensions or other properties
  • Comparative questions analyzing different configurations of parallelepipeds

Strategies for Solving Questions

Some key tips for mastering parallelepiped questions are:

  • Practice visualizing parallelepipeds and manipulating them
  • Understand logic behind formulas, don't just memorize them
  • Refer solutions of previous years' SSC CGL questions
  • Use online learning resources for comprehensive learning

Online Resources

Many websites offer useful study materials on rectangular parallelepipeds such as:

  • Tutorials and articles explaining concepts
  • Videos providing step-by-step solutions
  • Practice question banks
  • Mock tests and quizzes for self-analysis

Important Factors for Success

Key things to remember when learning this topic:

  • Focus on understanding concepts over rote learning formulas
  • Apply formulas accurately in appropriate contexts
  • Develop strong logical reasoning and 3D visualization skills
  • Practice, practice, practice - nothing beats solving questions

Common Mistakes to Avoid

Some mistakes to watch out for:

  • Blindly applying formulas without contextual analysis
  • Assuming all faces/edges equal when unequal dimensions given
  • Mixing up surface area, volume and diagonal formulas
  • Incorrect 3D visualization resulting in choice of wrong formula


With comprehensive concept clarity and rigorous practice, mastering rectangular parallelepipeds for SSC CGL is very much achievable. This quick visual guide summarizes the key focus areas:

Focus Area Key Points
Knowledge Understand properties, formulas
Comprehension Apply knowledge accurately in questions
Practice Solve previous years' papers, mock tests
Analysis Identify weak areas and improve

With the right strategy and tools, this syllabus area will no longer seem intimidating!

Frequently Asked Questions

Q1: How is a rectangular parallelepiped different from a cube?

A1: A cube has all sides of equal length, while a rectangular parallelepiped has unequal side lengths.

Q2: What are the minimum number of dimensions required to calculate the volume of a rectangular parallelepiped?

A2: You need the length, breadth and height - so 3 dimensions are needed to calculate the volume using the formula V=lxbxh.

Q3: Can you determine the surface area if only the volume is given?

A3: No, to calculate the surface area using the formula SA=2(lb+bh+hl), you need to know at least the length, breadth and height. Volume alone is not sufficient.

Q4: Is it possible for two rectangular parallelepipeds to have the same volume but different total surface areas?

A4: Yes, if the length, breadth and heights differ between the parallelepipeds, they can potentially have equal volumes but different surface areas.

Q5: If a parallelepiped has dimensions 2cm x 3cm x 4cm, what is its space diagonal?

A5: Using the formula for space diagonal (d2 = l2 + b2 + h2), the space diagonal is 5cm.

Q6: Can you inscribe a sphere within a rectangular parallelepiped?

A6: Yes, it is possible to inscribe a maximum-sized sphere within a rectangular parallelepiped by placing the sphere's center at the intersection of the diagonals.