3D Geometry Important Question

Duration: 5 min

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Module outline

  1. Communication Round: Vocabulary, Subject Verb Agreement (Verb Noun Agreement), Tenses, Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Cloze Test (Cloze Passage), Sentence Correction (Error Correction), Sentence Completion (Fill in the blanks), Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Direct and Indirect Speech, Active Passive Voice (Voice), Verbal Analogy (Word Based Analogy), Articles, Preposition, Conjunction, Sentence Construction, English Writing Ability, Communication Assessment
  2. Quantitative Aptitude: Ratio and Proportion (Ratios), Divisibility Rules, Data Interpretation, Mixture and Alligation, Permutation and Combination, Logarithm, Number System, HCF LCM, Speed Time and Distance, Percentage, Average, Powers and Exponents (Surds and Indices), Time and Work, Mensuration and Geometry, Age Problems, Pipe and Cistern, Probability, Profit and Loss, Simple Interest and Compound Interest, Algebra
  3. Analytical and Logical Reasoning: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Data Sufficiency, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Directions (Direction Test), Ranking, Order and Sequence, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Selection Decision Table (Decision Making), Logical Sequence Of Words, Puzzle Solving (Puzzles), Syllogisms, Seating Arrangements, Calendar, Clock, Blood Relations, Cubes & Dices, Venn Diagram, Analytical Reasoning (Counting Figures Reasoning)
  4. Cognizant Gaming Aptitude: Gamified / Game Based Aptitude
  5. Java (Cluster 1): Java
  6. ANSI SQL MySQL (Cluster 1,2,3): SQL
  7. HTML, CSS, JavaScript (Cluster 1,3): HTML, CSS, JavaScript
  8. Python (Cluster 2): Python for Placements by Yash Sir
  9. Cloud Fundamentals (Cluster 2): Emerging Tech Trends
  10. C# (Cluster 3): C#
  11. OOPs: Object Oriented Programming (OOPS)
  12. Technical Assessment (Coding): Coding Questions by Yash Sir, C Programming by Yash Sir, Programming in C++, Pseudo Codes
  13. Data Structures: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing
  14. DBMS: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, Relational Calculus, Transaction Management, Concurrency Control, Database Recovery, ORDBMS, Database Security & Authorization, Query Processing & Optimization, Enhanced Data Models, Data Warehousing & Mining, Big Data Systems, NoSQL
  15. Operating Systems: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Deadlock, Threads & Process Creation, Memory Management, Virtual Memory, Disc Scheduling, File Management, Windows OS, Linux OS, Security, Distributed Systems, Virtual Machines
  16. Computer Networks: Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, DLL: Error Control, DLL: Framing, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Net Layer:Routing Protocol, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware basics, Network Security, Mobile Technology, Cloud Computing and IoT, Cyber and Info Security
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This bilingual 3D geometry lesson solves a right-prism problem: the triangular base has sides 20 cm, 21 cm and 29 cm; volume is 7560 cm³; find lateral surface area. The instructor first computes the base perimeter P = 20 + 21 + 29 = 70 cm. A red right-triangle is sketched on the prism’s end face, and the Pythagorean check 20² + 21² = 29² (400 + 441 = 841) confirms the base is a right triangle, so its area is ½ × b × h = ½ × 20 × 21 = 210 cm². Using volume V = base area × prism height, the instructor finds h = 7560 / 210 = 36 cm. Finally, lateral surface area LSA = P × h = 70 × 36 = 2520 cm², matching option 4. The method emphasizes recognizing a right-triangle base from side lengths, computing area via ½bh, extracting prism height from volume, and applying LSA = perimeter × height.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The bilingual problem is displayed in English and Hindi: a right-prism with triangular base sides 20 cm, 21 cm, 29 cm and volume 7560 cm³; options are 2448, 2556, 2484, 2520 cm². A light-blue wireframe triangular prism appears at lower left. The instructor begins red handwritten work: perimeter P = 20 + 21 + 29 = 70 cm, then boxes the triangle area formula ½ × b × h and sketches a red right-triangle on the prism’s end face to mark base and height.

  2. 2:00 – 4:39 02:00-04:39

    The instructor verifies the base is a right triangle by writing 20² + 21² = 29² and 400 + 441 = 841, then computes base area as ½ × 20 × 21 = 210 cm². Using volume, the prism height is found: h = 7560 / 210 = 36 cm. The lateral surface area is then calculated with LSA = P × h = 70 × 36 = 2520 cm², and the answer is circled as option 4.

The lesson teaches a systematic approach to right-prism lateral surface area when the base is a triangle. Key steps: (1) compute perimeter from side lengths; (2) test for a right triangle using the Pythagorean theorem to justify area = ½bh; (3) compute base area; (4) derive prism height from V = base area × h; (5) apply LSA = perimeter × height. The worked example yields 2520 cm², reinforcing that lateral surface area depends only on base perimeter and prism height, not on the shape’s internal angles once area is known.

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