Answer: (3) 5+3+3+4
NEP 2020 restructures the school system into four stages: Foundational (5 years: Age 3–8, i.e., pre-primary 3 years + Grades 1–2), Preparatory (3 years: Grades 3–5), Middle (3 years: Grades 6–8), and Secondary (4 years: Grades 9–12). This replaces the old 10+2 structure. The new system covers ages 3–18 years, recognizing Early Childhood Care and Education (ECCE) as foundational. This is one of NEP 2020’s most fundamental structural changes.

Answer: (3) Mother tongue / Home language / Regional language
NEP 2020 strongly recommends that the medium of instruction up to at least Grade 5 (preferably Grade 8 and beyond) should be the home language, mother tongue, or local/regional language. This is based on research showing children learn best in their native language in early years. This does not mean English will not be taught — it will be taught as a subject. Both public and private schools are encouraged to follow this guideline.

Answer: (2) 50% by 2035
NEP 2020 aims to achieve a Gross Enrolment Ratio (GER) of 50% in higher education by 2035, up from about 26.3% in 2018. GER measures the percentage of the relevant age group (18–23 years) enrolled in higher education. NEP 2020 also proposes to set up multidisciplinary universities and colleges to increase access, and introduce multiple entry/exit options with an Academic Bank of Credits (ABC).

Answer: (1) UGC (University Grants Commission)
NEP 2020 recommends replacing the UGC, AICTE, and NAAC with a single apex body called the Higher Education Commission of India (HECI) having four verticals: NHERC (National Higher Education Regulatory Council), NAC (National Accreditation Council), HEGC (Higher Education Grants Council), and GEC (General Education Council). This is to eliminate overlapping regulatory bodies and create a unified framework for higher education governance.

Answer: (2) A digital storehouse where students’ academic credits can be stored and transferred
The Academic Bank of Credits (ABC) is a digital platform that stores academic credits earned by students from various higher education institutions. Students can deposit, accumulate, and transfer credits, enabling them to pursue education from multiple institutions. This facilitates the Multiple Entry and Exit system: students can exit after 1 year (certificate), 2 years (diploma), 3 years (degree), or 4 years (research-linked degree), and re-enter later.

Answer: (1) Nirmala Sitharaman
Nirmala Sitharaman presented the Union Budget 2025–26 on 1 February 2025. It was her 8th consecutive Union Budget, making her the Finance Minister to present the most budgets in Indian history. Key highlights of Budget 2025–26 include: new income tax slabs (no tax up to ₹12 lakh), increased capital expenditure, focus on MSMEs, and continuation of PM Gati Shakti for infrastructure. She has been Finance Minister since May 2019.

Answer: (4) 2047
Viksit Bharat @2047 (Developed India by 2047) is the vision of PM Narendra Modi to make India a fully developed nation by 2047 — the 100th year of independence. The vision has four pillars: (1) Prosperous Bharat, (2) Capable Bharat, (3) Sustainable Bharat, (4) Inclusive Bharat. It targets a GDP of US$30 trillion (from ~$3.5 trillion currently) and first-world quality of life for all citizens by 2047.

Answer: (2) Droupadi Murmu
Droupadi Murmu was elected as the 15th President of India (not 16th — India’s 15th President) on 25 July 2022. She is the first tribal woman and second woman to become President of India (after Pratibha Patil). She belongs to the Santali tribal community of Odisha. Jagdeep Dhankhar became the 14th Vice President of India in 2022. Ram Nath Kovind was the 14th President.

Answer: (3) New Delhi (Bharat Mandapam)
India hosted the G20 Summit 2023 on 9–10 September 2023 at Bharat Mandapam, New Delhi. India held the G20 Presidency from December 2022 to November 2023, under the theme “Vasudhaiva Kutumbakam” (One Earth, One Family, One Future). A landmark achievement was the inclusion of the African Union as a permanent G20 member. The next G20 Summit (2024) was hosted by Brazil, and 2025 by South Africa.

Answer: (3) Installing rooftop solar panels (up to 300 units free/month)
The Pradhan Mantri Surya Ghar: Muft Bijli Yojana was launched by PM Modi on 13 February 2024. It aims to provide up to 300 units of free electricity per month to 1 crore households by installing rooftop solar panels. The government provides heavy subsidy for solar panel installation. This is part of India’s push for renewable energy and its commitment to achieve 500 GW of non-fossil fuel energy by 2030.

Answer: (3) The Sun
Aditya-L1 is India’s first solar mission launched by ISRO on 2 September 2023. It is placed at the Lagrange Point 1 (L1) — a stable point between Earth and the Sun — providing a continuous, unobstructed view of the Sun. It carries 7 payloads to study solar corona, solar winds, solar flares, and space weather. It was successfully inserted into the L1 halo orbit on 6 January 2024. Aditya means “Sun” in Sanskrit.

Answer: (2) False — He won Silver medal at Paris 2024
Neeraj Chopra won the Silver medal in Javelin Throw at the Paris Olympics 2024 with a throw of 89.45 m. The Gold was won by Pakistan’s Arshad Nadeem (92.97 m — Olympic record). Neeraj had won Gold at Tokyo Olympics 2020. India won a total of 6 medals at Paris 2024. India’s only Gold at Paris 2024 was won by Shooter Manu Bhaker – actually she won 2 Bronzes. India’s total: 1 Silver (Neeraj), 5 Bronze = 6 medals.

Answer: (3) Article 280
The Finance Commission is constituted under Article 280 of the Indian Constitution. It is a quasi-judicial body set up every five years to recommend distribution of tax revenues between the Centre and States. The 16th Finance Commission has been constituted for the period 2026–31 under Dr. Arvind Panagariya. The 15th Finance Commission (2021–26) was headed by N.K. Singh.

Answer: (2) Dadabhai Naoroji
Dadabhai Naoroji (Grand Old Man of India) propounded the ‘Drain of Wealth’ theory in his book “Poverty and Un-British Rule in India” (1901). He argued that British rule was systematically draining India’s wealth — through trade surplus going to Britain, salaries of British officers, and military expenditure for British interests. He was the first Indian to be elected to the British Parliament (1892). R.C. Dutt wrote “Economic History of India” supporting Naoroji’s thesis.

Answer: (4) Mirzapur / Allahabad (Prayagraj)
India’s Standard Time (IST) is based on the 82°30’E meridian, which passes through Mirzapur (near Allahabad/Prayagraj), Uttar Pradesh. IST = UTC + 5:30 hours. India has a single time zone despite spanning nearly 30° of longitude (68°E to 97°E). The clock tower at Mirzapur (Shankar Ghadi) was historically used to set Indian Standard Time. This avoids multiple time zones but means sunrise/sunset times vary greatly across the country.

Answer: (3) European Union (EU)
The European Union (EU) passed the world’s first comprehensive Artificial Intelligence Act (EU AI Act) in March 2024, which came into force in August 2024. It classifies AI systems by risk level (unacceptable, high, limited, minimal) and bans certain uses like real-time facial recognition in public spaces. India is developing its own AI regulatory framework. The USA issued an Executive Order on AI safety in October 2023.

Answer: (3) 6.4%
The Economic Survey 2024–25 (presented on 31 January 2025, the day before the Union Budget) projected India’s GDP growth at 6.4% for 2024–25. The survey is prepared by the Chief Economic Adviser (CEA) — currently V. Anantha Nageswaran. India remains one of the fastest-growing major economies despite global slowdowns. The IMF and World Bank also projected India’s growth at around 6.5% for 2025.

Answer: (3) 2070
India committed to achieving net-zero carbon emissions by 2070 at the COP26 Glasgow Summit (November 2021). India’s updated NDC (Nationally Determined Contribution) targets: (1) 500 GW renewable energy capacity by 2030; (2) 50% cumulative electric power from non-fossil sources by 2030; (3) Reduce GDP emission intensity by 45% by 2030. Compare: China = 2060, USA/EU = 2050, UK = 2050. India’s 2070 target reflects its developing nation status.

Answer: (3) 1 November 1956
West Bengal was reorganized as a separate state on 1 November 1956 following the States Reorganisation Act, 1956, which reorganized Indian states on linguistic lines based on the Fazl Ali Commission report. After Partition in 1947, West Bengal was carved out of undivided Bengal. The state includes the Darjeeling hills (added 1954), the Cooch Behar and Chandernagore mergers (1949–50), and later exchanges with Pakistan. West Bengal has 23 districts and the capital is Kolkata.

Answer: (3) Grade 6
NEP 2020 proposes that vocational education will be integrated into all schools from Grade 6 onwards. From Grade 6, students will be exposed to vocational subjects like carpentry, electronics, metalwork, gardening, pottery etc., through internships with local craftsmen and industries. By 2025, NEP aims to cover at least 50% of learners through vocational education at school and higher education levels. This aims to remove the social stigma attached to vocational education.

Answer: (2) Wise and careful
Prudent means acting with or showing care and thought for the future; wise in practical matters. Synonyms: Wise, Careful, Sensible, Judicious, Discreet, Cautious, Sagacious. Antonyms: Reckless, Imprudent, Careless, Foolish. Example: “A prudent investor never puts all eggs in one basket.” Related noun: Prudence. The word comes from Latin prudens = foresighted.

Answer: (3) Lazy / Negligent
Diligent means having or showing care and conscientiousness in one’s work or duties. Its antonym is Lazy/Negligent/Idle/Indolent. Synonyms of Diligent: Hardworking, Industrious, Assiduous, Painstaking, Meticulous. Example: “A diligent student revises daily; a lazy student waits for the last minute.” This word pair (Diligent–Lazy) is among the top vocabulary pairs tested in WBSSC exams.

Answer: (3) Achieve
Correct spelling: Achieve. The rule: “i before e, except after c” — “achieve” follows this rule. Similarly: Believe, Relieve, Field, Yield, Brief. After ‘c’: Receive, Deceive, Ceiling, Perceive (e before i). Other correct spellings: Receive (not recieve). Common mistake: writing “acheive” — the ‘c’ and ‘h’ together make the /tʃ/ sound, and the vowel is ‘ie’ not ‘ei’.

Answer: (3) to
“Looking forward to” is a fixed phrase (phrasal verb). Importantly, the “to” here is a preposition (not part of an infinitive), so it must be followed by a gerund (V+ing): “looking forward to meeting you.” Other examples: “I look forward to hearing from you.” “She is looking forward to starting her new job.” Common error: using “look forward to + infinitive” (meet instead of meeting).

Answer: (3) Syllabi or Syllabuses (both accepted)
Syllabus has two accepted plurals: Syllabi (Latin form) and Syllabuses (Anglicized form). Both are correct. Similarly: Cactus → Cacti/Cactuses; Focus → Foci/Focuses; Fungus → Fungi/Funguses; Radius → Radii; Index → Indices/Indexes; Appendix → Appendices/Appendixes. In Indian exam contexts, “Syllabi” is often preferred. “Syllabii” with double ‘i’ is always wrong.

Answer: (2) To endure a painful situation with courage
“Bite the bullet” means to accept and endure a painful, difficult, or unpleasant situation with courage and determination. Origin: Soldiers in pre-anesthesia days bit a bullet during surgery to cope with the pain. Example: “I didn’t want to apologize but I bit the bullet and did it.” Similar idioms: “Grin and bear it” (endure without complaint), “Face the music” (accept consequences bravely).

Answer: (3) He doesn’t know the answer.
Present Simple negative: 3rd person singular (he/she/it) → does not (doesn’t) + V1. “He doesn’t know the answer.” ✓ Errors: “don’t” → used for I/You/We/They (not He/She/It); “didn’t knew” → “knew” is V2, but after ‘did/didn’t’ always use V1 (know); “not knowing” → incomplete construction. Golden rule: He/She/It → does/doesn’t + base verb (V1).

Answer: (3) All applications are being reviewed by the manager.
Tense: Present Continuous Active → Passive rule: Object + is/am/are being + V3 + by agent. “The manager is reviewing all applications” → “All applications are being reviewed by the manager.” ✓ Present Continuous Passive = am/is/are + being + past participle. Note: “were reviewed” = Simple Past Passive; “have been reviewed” = Present Perfect Passive.

Answer: (2) Bilingual
A person who can speak two languages = Bilingual. Key language-related terms: One language = Monolingual; Two languages = Bilingual; Three languages = Trilingual; Many languages = Polyglot/Multilingual; Study of language = Linguistics; A person who studies languages = Linguist. India officially follows a three-language formula (recommended by NEP 2020 as well): Hindi, English, and a regional language.

Answer: (1) A — “suggested me” is incorrect
The verb “suggest” does NOT take an indirect object with a pronoun directly. Correct structures: (a) “She suggested that I apply for the government job.” (b) “She suggested applying for the government job.” (c) “She advised me to apply…” (‘Advise’ can take object + to-infinitive; ‘suggest’ cannot). Common error: treating ‘suggest’ like ‘advise’. “Suggested me to apply” is always wrong.

Answer: (4) Lentil
Wheat, Rice, and Maize are all cereal crops (grains) — they belong to the grass family (Poaceae). Lentil is a pulse/legume crop (family Fabaceae/Leguminosae). Pulses are protein-rich and fix nitrogen in soil. Other pulses: Chickpea, Moong, Arhar/Toor, Urad. Cereals are carbohydrate-rich. The odd one out is Lentil because it is the only pulse/legume in the list.

Answer: (3) 224
Pattern: Each term is multiplied by 2. 7×2=14, 14×2=28, 28×2=56, 56×2=112, 112×2=224. This is a geometric progression (GP) with first term a=7 and common ratio r=2. Powers of 2 multiplied by 7: 7×2¹=14, 7×2²=28, 7×2³=56, 7×2⁴=112, 7×2⁵=224. Doubling series are very common in WBSSC reasoning sections.

Answer: FSBTFS
Check PENCIL → QFODKM: P(16)→Q(17)+1; E(5)→F(6)+1; N(14)→O(15)+1; C(3)→D(4)+1; I(9)→K(11)+2?? No. Let’s recheck: P→Q(+1), E→F(+1), N→O(+1), C→D(+1), I→K: I=9, K=11 (+2). L→M: L=12, M=13(+1). So mostly +1 but I→K is +2. Pattern might alternate: +1,+1,+1,+1,+2,+1. Alternatively: PENCIL→QFODKM: each letter +1 except 5th letter I→K(+2). ERASER: E→F(+1), R→S(+1), A→B(+1), S→T(+1), E→G(+2?), R→S(+1) = F-S-B-T-G-S = FSBTGS? Or consistently +1: E→F,R→S,A→B,S→T,E→F,R→S = FSBTFS. Applying consistent +1 to all: ERASER = FSBTFS. Answer: (1) or (3) FSBTFS.

Answer: (3) U
Pattern: A(1), E(5), I(9), M(13), Q(17), U(21). Each letter skips 3 letters (adds 4 positions): A→E(+4), E→I(+4), I→M(+4), M→Q(+4), Q→U(+4). Positions: 1, 5, 9, 13, 17, 21. These are letters at positions that follow the arithmetic sequence 1+4n (n=0,1,2…). U is the 21st letter of the alphabet. Next would be Y(25).

Answer: (3) No definite conclusion about Sharma’s profession
Logic: “All politicians are liars” means Politicians ⊂ Liars. But NOT all liars are politicians — there can be liars who are not politicians. Sharma being a liar does NOT confirm he is a politician. This is the logical fallacy of “affirming the consequent”: just because P→Q (politician→liar) is true, Q→P (liar→politician) is NOT necessarily true. No definite conclusion can be drawn about Sharma being a politician.

Answer: P is the grandmother of S
P − Q: P is the mother of Q. Q + R: Q is the father of R. R × S: R is the brother of S. Chain: P is mother of Q → Q is father of R and S (since R is brother of S, they share the same parent Q) → P is the grandmother of S (mother’s mother-in-law path: P→Q(son)→R&S(grandchildren)). P = grandmother of S. ✓

Answer: 34
Formula: Total = Rank from top + Rank from bottom − 1 = 12 + 23 − 1 = 34. Reasoning: 11 students above Suresh + Suresh himself + 22 students below = 11+1+22 = 34. Verification: Rank from top=12 → 12th from top ✓; 34−12+1=23rd from bottom ✓. This formula (top+bottom−1) is universally applicable for all “total students in a row/class” problems.

Answer: North-West
Starting direction: South-West (SW). Turning 90° clockwise: SW → NW (North-West). Clockwise rotation of 90° from any direction: N→E, E→S, S→W, W→N, NE→SE, SE→SW, SW→NW, NW→NE. So from South-West, turning 90° clockwise = North-West. Visual tip: draw a compass rose and rotate 90° clockwise from SW — it lands on NW.

Answer: (3) Artefacts / Exhibits
Analogy: A Library is a place that contains and stores Books. Similarly, a Museum is a place that contains and displays Artefacts/Exhibits (historical objects, art, specimens). The relationship is “Place → What is stored/kept there.” Other examples: Hospital→Patients, Granary→Grain, Aviary→Birds, Aquarium→Fish, Zoo→Animals.

Answer: (4) Friday
100 days from Wednesday: 100 ÷ 7 = 14 weeks remainder 2. So 100 days later = Wednesday + 2 days = Friday. Formula: Find remainder when days are divided by 7. Days of week cycle every 7 days. Remainder 0 = same day; 1 = next day; 2 = two days ahead, etc. Wednesday(4th day if Sun=1) + 2 = Friday(6th day). ✓

Answer: (3) 72
18 = 2×3², 24 = 2³×3, 36 = 2²×3². LCM = highest powers = 2³×3² = 8×9 = 72. Verification: 72÷18=4 ✓, 72÷24=3 ✓, 72÷36=2 ✓. LCM takes the highest power of each prime factor across all numbers.

Answer: (3) 39
BODMAS — Division and Multiplication left to right first: 144÷12 = 12; 12×3 = 36. Then Addition and Subtraction left to right: 36+8 = 44; 44−5 = 39. Full working: 144÷12×3+8−5 = 12×3+8−5 = 36+8−5 = 44−5 = 39.

Answer: (2) 5 days
A’s rate = 1/10, B’s = 1/15, C’s = 1/30. Combined = 1/10+1/15+1/30. LCM of 10,15,30 = 30. Combined = 3/30+2/30+1/30 = 6/30 = 1/5 per day. Time = 5 days. Always take LCM of denominators to add fractions easily. Verification: In 5 days: A does 5/10=1/2, B does 5/15=1/3, C does 5/30=1/6. 1/2+1/3+1/6 = 3/6+2/6+1/6 = 6/6 = 1 ✓.

Answer: (3) 20 sec
Total distance = train length + bridge length = 250+150 = 400 m. Speed = 72 km/h = 72×(5/18) = 20 m/s. Time = 400÷20 = 20 seconds. Key: When a train crosses a bridge or platform, total distance = (train length + bridge/platform length). Convert km/h to m/s by multiplying ×5/18.

Answer: (3) ₹12000
A:B = 5:4. Difference = 5k−4k = k = ₹3000. B = 4k = 4×3000 = ₹12000. A = 5×3000 = ₹15000. Verification: A−B = 15000−12000 = ₹3000 ✓. Ratio = 15000:12000 = 5:4 ✓. When ratio difference and actual difference are given, find the value of one part (k) first.

Answer: (3) 40
Original sum = 8×40 = 320. Remove 30 and 50: new sum = 320−30−50 = 240. New count = 8−2 = 6. New average = 240÷6 = 40. The average remains 40 because the two removed numbers (30 and 50) average out to exactly 40 — the same as the group average. So removing them doesn’t change the average. This is an elegant conceptual point.

Answer: (3) 23.07%
Let B = 100. A = 130 (30% more than B). B is less than A by = (130−100)/130 × 100 = 30/130 × 100 = 23.07%. Formula: If X is r% more than Y, then Y is less than X by [r/(100+r)]×100 %. Here: [30/130]×100 = 23.07%. Common trap: answering 30% (same percentage). The base changes — B is compared against A now, not against B.

Answer: (3) ₹720
After 10% discount: 1000×0.90 = ₹900. After 20% discount on ₹900: 900×0.80 = ₹720. Note: Two successive discounts of 10% and 20% ≠ 30% total discount. Equivalent single discount = 1−(0.9×0.8) = 1−0.72 = 28%. So total discount = 28% on ₹1000 = ₹280. SP = 1000−280 = ₹720 ✓. Always apply discounts successively, not by addition.

Answer: (3) ₹2580
A = P(1+r/100)ⁿ = 8000×(1.15)² = 8000×1.3225 = ₹10580. CI = A−P = 10580−8000 = ₹2580. Or step-by-step: Year 1 interest = 15% of 8000 = ₹1200. Amount after Year 1 = ₹9200. Year 2 interest = 15% of 9200 = ₹1380. Total CI = 1200+1380 = ₹2580. Verification: SI for 2 years = (8000×15×2)/100 = ₹2400. CI (₹2580) > SI (₹2400) ✓.

Answer: (3) 12.5%
If principal = P, it doubles → Amount = 2P. SI = 2P−P = P. Formula: SI = (P×R×T)/100 → P = (P×R×8)/100 → R = 100/8 = 12.5%. Quick shortcut: Rate = 100/T (when money doubles at SI). Always: If money doubles in n years at SI → R = 100/n%. If triples: R = 200/n%. Verification: SI = (P×12.5×8)/100 = P ✓.

Answer: (3) 7
2x − 3 = 11 → 2x = 11+3 = 14 → x = 14÷2 = 7. Verification: 2(7)−3 = 14−3 = 11 ✓. Linear equations: always isolate the variable. Step 1: Move constants to one side (add 3 to both sides). Step 2: Divide by coefficient of x. This is the most basic type of linear equation and appears in every competitive exam.

Answer: (3) 48 cm²
Area of triangle = (1/2) × base × height = (1/2) × 12 × 8 = (1/2) × 96 = 48 cm². Common error: Forgetting the 1/2 factor → getting 96 cm² (option D). Key formulas: Triangle = ½bh; Rectangle = l×b; Square = a²; Circle = πr²; Parallelogram = b×h; Trapezium = ½(a+b)×h.

Answer: (3) 15 min
A fills 1/20, B fills 1/30, C empties 1/60 per minute. Net rate = 1/20+1/30−1/60. LCM=60: 3/60+2/60−1/60 = 4/60 = 1/15 per minute. Time = 15 minutes. Remember: filling pipes are positive, emptying pipe is negative. Verification: In 15 min → A fills 15/20=3/4; B fills 15/30=1/2; C empties 15/60=1/4. Net = 3/4+1/2−1/4 = 3/4+2/4−1/4 = 4/4 = 1 ✓.

Answer: (3) 56.25%
CP of 1 mango = 4/5 = ₹0.80. SP of 1 mango = 5/4 = ₹1.25. Profit per mango = 1.25−0.80 = ₹0.45. Profit% = (0.45/0.80)×100 = (45/80)×100 = 56.25%. Or: LCM of 5&4=20 mangoes. CP of 20 = 4×4 = ₹16. SP of 20 = 5×5 = ₹25. Profit = 25−16 = ₹9. Profit% = (9/16)×100 = 56.25%.

Answer: (3) 154 cm²
Circumference = 2πr = 44 → r = 44/(2×22/7) = 44×7/44 = 7 cm. Area = πr² = (22/7)×7² = (22/7)×49 = 22×7 = 154 cm². Key: First find radius from circumference, then use it to find area. Circle formulas: Circumference = 2πr; Area = πr²; Diameter = 2r.

Answer: (3) 50%
20% failed in both → 80% passed in at least one subject. Using set formula: Passed in both = Passed in English + Passed in Maths − Passed in at least one = 60+70−80 = 50%. Formula: n(A∪B) = n(A) + n(B) − n(A∩B) → 80 = 60+70−n(A∩B) → n(A∩B) = 130−80 = 50%.

Answer: (3) 8 km/h
Speed in still water = (Downstream + Upstream)/2 = (10+6)/2 = 16/2 = 8 km/h. Speed of stream (current) = (Downstream − Upstream)/2 = (10−6)/2 = 2 km/h. Key formulas: Speed in still water = (D+U)/2; Speed of stream = (D−U)/2. Verification: 8+2=10 (downstream) ✓; 8−2=6 (upstream) ✓.

Answer: (3) 0.13
√(0.0169) = √(169/10000) = √169/√10000 = 13/100 = 0.13. Method: Convert decimal to fraction, take square root of numerator and denominator separately. √169 = 13; √10000 = 100; Answer = 13/100 = 0.13. Verification: 0.13² = 0.0169 ✓. Always convert decimals to fractions when finding square roots.

Answer: ₹2000
Let sum at 6% = x. Sum at 9% = (5000−x). Interest equation: (x×6×1)/100 + (5000−x)×9×1/100 = 390. → 6x/100 + (45000−9x)/100 = 390. → 6x + 45000 − 9x = 39000. → −3x = −6000. → x = ₹2000. Verification: Interest at 6% = (2000×6)/100=₹120; at 9% = (3000×9)/100=₹270. Total=₹390 ✓.

Answer: (3) 100 cm²
Diagonal of square = a√2, where a = side. Given: a√2 = 10√2 → a = 10 cm. Area = a² = 10² = 100 cm². Or use formula: Area of square = (diagonal)²/2 = (10√2)²/2 = 200/2 = 100 cm² ✓. Key: Diagonal of square = side × √2. This formula is useful for both finding the side from diagonal and the area directly from diagonal.