Mensuration Questions

Multiple choice
  1. 27.72 cm.2/ सेमी.2

  2. 55.44 cm.2/ सेमी.2

  3. 9.24 cm.2/ सेमी.2

  4. 13.86 cm.2/ सेमी.2

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Total surface area of hemisphere = 3πr². Curved surface area = 2πr². Therefore, curved surface area = (2/3) × total surface area = (2/3) × 41.58 = 27.72 cm².

Multiple choice
  1. 64 cm.2/सेमी.2

  2. 81 cm.2/सेमी.2

  3. 100 cm.2/सेमी.2

  4. 36 cm.2/सेमी.2

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Area of incircle = 16π = πr², so radius r = 4 cm. For a square, the incircle touches all four sides, meaning the diameter equals the side length. Therefore, square side = 2r = 8 cm. Area of square = side² = 8² = 64 cm². The relationship between incircle radius and square side is the key insight.

Multiple choice
  1. $896 cm3$
  2. $1288 cm3$
  3. $985 cm3$
  4. $869 cm3$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When 4cm squares are cut from each corner and folded up, the new box dimensions are: length = 40-2(4) = 32cm, width = 15-2(4) = 7cm, height = 4cm. Volume = length × width × height = 32 × 7 × 4 = 896 cm³. This is an optimization problem where cutting squares creates an open box.

Multiple choice
  1. If only statement I is sufficient.

  2. If only statement II is sufficient.

  3. If either I or II is sufficient.

  4. If neither I nor II is sufficient.

  5. If both statements I and II are necessary.

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Statement I: Circumference = 220m. Cost = 220 × 40 = Rs. 8800 (sufficient). Statement II: Area = 616 = πr² gives r = 14m. Circumference = 2πr = 88m. Cost = 88 × 40 = Rs. 3520 (sufficient). Since either statement alone is sufficient, answer is C.

Multiple choice
  1. 2 : 3

  2. 3 : 5

  3. 4 : 5

  4. 4 : 9

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

For hemispheres, the ratio of curved surface areas is (4πr²/2) : (4πR²/2) = r² : R². Since volume of hemisphere = (2/3)πr³, the radii are proportional to the cube roots of volumes. r ∝ ³√25.6 ≈ 2.96, R ∝ ³√86.5 ≈ 4.42. Therefore, r² : R² = (2.96)² : (4.42)² = 8.76 : 19.54 ≈ 4:9. The key insight is that surface area ratio is the square of the cube root ratio of volumes.

Multiple choice
  1. 880

  2. 1188

  3. 594

  4. 440

  5. None of these

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

An open-top cylindrical box requires the base area (circular) plus the lateral (curved) surface area. Base area = πr² = (22/7)×7×7 = 154 cm². Lateral area = 2πrh = 2×(22/7)×7×10 = 440 cm². Total = 154 + 440 = 594 cm².

Multiple choice
  1. All I, II and III

  2. II alone and I and III together

  3. I and II together

  4. II and III alone

  5. II alone

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Volume of cylinder = πr²h. New radius = 1.2r, new height = 1.1h. New volume = π(1.2r)²(1.1h) = 1.584πr²h. Increase = 58.4%. Statement II alone gives the formula and percentage increases needed. Statements I and III about ice cube (10cm height in 10L water) are irrelevant to calculating the percent increase in cylinder volume. Option B 'II alone and I and III together' is poorly worded but suggests II is the key.

Multiple choice
  1. All

  2. I and II

  3. Any one

  4. I and either II or III

  5. Can not be answered even with all the these statements together.

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Statement I (perimeter = 44 m) and Statement II (height = 10 m) together are sufficient. The total wall area = perimeter × height = 44 × 10 = 440 sq m. Cost = 440 × 25 = Rs 11,000. Statement III alone is insufficient, and I + III can solve but are not required when both I and II are available.

Multiple choice
  1. 12 πm2

  2. 14 πm2

  3. 16 πm2

  4. 28 πm2

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

आयत के अंदर खींचा जा सकने वाला सबसे बड़ा वृत्त आयत की छोटी भुजा के बराबर व्यास वाला होता है। यहां छोटी भुजा 8m है, इसलिए त्रिज्या 4m होगी। वृत्त का क्षेत्रफल = πr² = π × 4² = 16π m²। विकल्प A और B गलत गणना से आते हैं, जबकि D अधिक है।

Multiple choice
  1. 11 cm, 3 cm

  2. 9 cm, 4 cm

  3. 8 cm, 5 cm

  4. 9 cm, 5 cm

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For externally touching circles, distance between centers equals sum of radii: r1 + r2 = 14. Areas: pi*r1^2 + pi*r2^2 = 130*pi, so r1^2 + r2^2 = 130. Using (r1+r2)^2 = r1^2 + r2^2 + 2*r1*r2: 14^2 = 130 + 2*r1*r2, giving 196 - 130 = 2*r1*r2, so r1*r2 = 33. The factors of 33 that sum to 14 are 11 and 3. Check: 11+3=14, 11^2+3^2=121+9=130. Option B (9+4=13 not 14), C (8+5=13), D (9+5=14 but 81+25=106).

Multiple choice
  1. 125

  2. 165

  3. 145

  4. 135

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The area of the circular path equals the area of the outer circle minus the area of the inner garden. Inner radius is 21 m, outer radius is 21+3=24 m. Area = π(R² - r²) = π(24² - 21²) = π(576 - 441) = 135π m². Option D correctly shows 135.