3D Geometry Important Question

Duration: 5 min

This video lesson is available to enrolled students.

Inside: a video lesson and guided study material.

Module outline

Child Development and Pedagogy: Concept of Pedagogy, बालक कैसे सोचते एवं सीखते हैं / How Children Think and Learn, विकास की अवधारणा / Concept of Development, विकास के मनोवैज्ञानिक सिद्धांत / Psychological Theories of Development, Personality Development, व्यक्तिगत भिन्नताएँ, व्यक्तित्व एवं जेंडर / Individual Differences, Personality and Gender, संवेग, अभिप्रेरणा, मानसिक स्वास्थ्य एवं निर्देशन / Emotion, Motivation, Mental Health and Guidance, Understanding Diverse Learners, समावेशी शिक्षा / Inclusive Education, शिक्षण-अधिगम प्रक्रिया / Teaching-Learning Process, शिक्षण विधियाँ एवं रणनीतियाँ / Teaching Methods and Strategies, Experiential Pedagogy, आकलन एवं मूल्यांकन / Assessment and Evaluation, शैक्षिक विचारक, उद्देश्य एवं राष्ट्रीय नीतियाँ / Educational Thinkers, Aims and National Policies, Curriculum Framework & Reforms, Miscellaneous Topics, Nature, Objectives & Characteristics of Teaching, Learners & Learning Process, Factors Affecting Teaching, कक्षा प्रबंधन और सम्प्रेषण / Classroom Management and Communication, शिक्षण संसाधन और शैक्षिक प्रौद्योगिकी / Teaching Resources and Educational Technology, पाठ्यचर्या और विद्यालयी गतिविधियाँ / Curriculum and School Activities, पाठ योजना और शिक्षण कौशल / Lesson Planning and Teaching Skills, Evaluation, Assessment & Measurement, Inclusive Education & Special Needs, Guidance, Counselling & Mental Health, संविधान, आयोग, अधिनियम एवं योजनाएँ / Constitution, Commissions, Acts and Schemes in Education, अधिगम एवं इसके सिद्धांत / Learning and Its Theories, बुद्धि एवं सृजनात्मकता / Intelligence and Creativity
Language I — Hindi: भाषा, लिपि और वर्ण-विचार, संधि, शब्द-स्रोत और शब्द-रचना, समास, शब्द-भेद: विकारी और अविकारी, लिंग, वचन, कारक, काल और वाच्य, वाक्य-विचार और शुद्ध लेखन, शब्द-भंडार, रस, छंद, अलंकार और शब्द-शक्ति, हिंदी साहित्य, अपठित बोध, हिंदी शिक्षणशास्त्र
Language Pedagogy (Language I and II): Language Pedagogy (Hindi/English/Sanskrit/Urdu learning & teaching)
Language II — English: Sounds, Spelling and Word Formation, Parts of Speech, Nouns and Pronouns, Articles, Determiners and Adjectives, Verbs and Modals, Tenses and Subject–Verb Agreement, Adverbs, Prepositions and Conjunctions, Sentence Structure, Voice and Narration, Vocabulary, Sentence Correction and Writing Skills, Poetry and English Literature, Reading Comprehension, Pedagogy of English Language
Language II — Urdu: رسم الخط، املا اور تلفظ, ذخیرۂ الفاظ, قواعد, محاورے اور ضرب الامثال, شعر و سخن, اردو ادب کی تاریخ, تفہیمِ عبارت, اردو کی تدریس
Language II — Sanskrit: वर्णविचारः एवं संज्ञाप्रकरणम्, सन्धिप्रकरणम्, शब्दरूपाणि, धातुरूपाणि, कारकाणि एवं विभक्तयः, उपसर्गाः एवं अव्ययानि, प्रत्ययप्रकरणम्, समासप्रकरणम्, वाच्यप्रकरणम्, संख्याज्ञानम्, शब्दज्ञानम् एवं अनुवादः, अपठितावबोधनम्, संस्कृतसाहित्यम् एवं काव्यशास्त्रम्, संस्कृतशिक्षणशास्त्रम्
Mathematics: Mathematics Pedagogy, भिन्न एवं दशमलव / Fractions & Decimals, गुणनखंड, विभाज्यता, म.स.प. एवं ल.स.प. / Factors, Divisibility, HCF & LCM, प्रतिशत, लाभ-हानि एवं ब्याज / Percentage, Profit–Loss & Interest, अनुपात, समानुपात, औसत एवं आयु / Ratio, Proportion, Average & Ages, समय-कार्य एवं चाल-दूरी / Time & Work and Speed–Distance, बीजगणित / Algebra, त्रिभुज, चतुर्भुज, वृत्त एवं त्रिकोणमिति / Triangles, Quadrilaterals, Circles & Trigonometry, क्षेत्रमिति: परिमाप, क्षेत्रफल एवं आयतन / Mensuration: Perimeter, Area & Volume, आँकड़ा प्रबंधन, सांख्यिकी एवं प्रायिकता / Data Handling, Statistics & Probability, गणित शिक्षणशास्त्र / Mathematics Pedagogy, संख्या पद्धति एवं स्थानीय मान / Number System & Place Value, रेखाएँ, कोण, आकृतियाँ एवं निर्देशांक / Lines, Angles, Shapes & Coordinates, वर्ग, घन, घातांक एवं करणी / Squares, Cubes, Exponents & Surds, मूलभूत संक्रियाएँ, सरलीकरण एवं पैटर्न / Basic Operations, Simplification & Patterns, मापन: लंबाई, भार, धारिता, समय एवं मुद्रा / Measurement: Length, Mass, Capacity, Time & Money
Science: Science Pedagogy, भोजन, पोषण एवं स्वास्थ्य / Food, Nutrition and Health, रासायनिक अभिक्रियाएँ, अम्ल, क्षार एवं लवण / Chemical Reactions, Acids, Bases and Salts, बल, दाब, कार्य एवं ऊर्जा / Force, Pressure, Work and Energy, प्रकाश / Light, विद्युत एवं चुंबकत्व / Electricity and Magnetism, सजीव जगत: वर्गीकरण, कोशिका एवं ऊतक / Living World: Classification, Cell and Tissues, पादपों में पोषण, परिवहन एवं जनन / Plants: Nutrition, Transport and Reproduction, मानव शरीर एवं अंग तंत्र / Human Body and Organ Systems, पर्यावरण एवं पारिस्थितिकी / Environment and Ecology, धातु, अधातु एवं दैनिक उपयोग की सामग्री / Metals, Non-metals and Materials of Daily Use, प्रौद्योगिकी, मापन एवं गति / Technology, Measurement and Motion, ऊष्मा एवं ध्वनि / Heat and Sound, पदार्थ एवं उसकी संरचना / Matter and Its Structure, ब्रह्मांड एवं प्राकृतिक परिघटनाएँ / Universe and Natural Phenomena
Social Studies/Social Science: प्राचीन भारत का इतिहास / Ancient Indian History, मध्यकालीन भारत का इतिहास / Medieval Indian History, औपनिवेशिक भारत एवं समाज सुधार / Colonial India and Social Reform, भारतीय राष्ट्रीय आंदोलन एवं स्वतंत्र भारत / Indian National Movement and Independent India, विश्व इतिहास एवं अंतरराष्ट्रीय संबंध / World History and International Relations, पृथ्वी, ग्लोब एवं मानचित्र / Earth, Globe and Maps, भौतिक भूगोल / Physical Geography, प्राकृतिक वनस्पति, वन्य जीवन एवं विश्व के प्रदेश / Natural Vegetation, Wildlife and World Regions, भारत का भूगोल / Geography of India, संसाधन एवं विकास / Resources and Development, सामाजिक एवं राजनीतिक जीवन / Social and Political Life, भारतीय संविधान / Indian Constitution, सरकार: केंद्र, राज्य एवं स्थानीय / Government: Union, State and Local, Social Studies Pedagogy, उत्तर प्रदेश सामान्य ज्ञान / Uttar Pradesh GK, अर्थशास्त्र एवं भारतीय अर्थव्यवस्था / Economics and Indian Economy, सामाजिक विज्ञान शिक्षणशास्त्र / Social Science Pedagogy
Mathematics & Science (Video Lessons & Notes): Number System, Divisibility Rules, HCF LCM, Powers and Exponents (Surds and Indices), Algebra, Sequence and Series (Series), Ratio and Proportion (Ratios), Percentage, Profit and Loss, Simple Interest and Compound Interest, Time and Work, Pipe and Cistern, Mensuration and Geometry, Partnership, Statistics, Data Interpretation, Probability, Biology, Chemistry, Physics
Social Studies (Video Lessons & Notes): Geography, History, Polity, Environment, Static General Knowledge, State Wise GK

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

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.
2:00 – 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.