Mensuration Questions

Multiple choice
  1. 4 : 1

  2. 1 : 4

  3. 8 : 1

  4. 1 : 8

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

Let cylinder radius = R, ball radius = r. Cylinder volume = πR²h = πR³ (since R = h). 48 balls volume = 48 × (4/3)πr³. Equating: πR³ = 48 × (4/3)πr³, giving R³ = 64r³, so R/r = 4. Ratio of ball radius to cylinder radius = r:R = 1:4, which equals 4:1 when expressed as ball:cylinder ratio.

Multiple choice
  1. 520

  2. 544

  3. 540

  4. 534

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

Square base side = 16 m, height = 15 m. Slant height of each triangular face = √(8² + 15²) = 17 m (apothem of base = 8). Lateral surface area = 4 × area of one triangular face = 4 × (1/2 × 16 × 17) = 544 m².

Multiple choice
  1. 4 : 3

  2. 7 : 4

  3. 8 : 5

  4. 8 : 3

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

For a right pyramid with square base, perimeter 12m means each side is 3m, so base area = 9 m². Slant surface area = 4 × (1/2 × 3 × 4) = 24 m² (four triangular faces). Ratio = 24:9 = 8:3. Option D is correct.

Multiple choice
  1. $98$
  2. $146$
  3. $84$
  4. $168$
  5. $154$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

वर्गाकार प्लॉट का क्षेत्रफल = 28 × 28 = 784 वर्ग मीटर। वृत्ताकार बगीचे का व्यास = 28 मीटर, अतः त्रिज्या = 14 मीटर। वृत्त का क्षेत्रफल = πr² = (22/7) × 14² = (22/7) × 196 = 616 वर्ग मीटर। शेष स्थान = वर्ग का क्षेत्रफल - वृत्त का क्षेत्रफल = 784 - 616 = 168 वर्ग मीटर। यह समस्या वृत्त और वर्ग के क्षेत्रफलों के अंतर की गणना मांगती है।

Multiple choice
  1. 3850 cm2/सेमी2

  2. 1694 cm2/सेमी2

  3. 1925 cm2/सेमी2

  4. 1500 cm2/सेमी2

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

Area between concentric circles = π(R² - r²) where R = 42 cm (outer radius) and r = 35 cm (inner radius). Area = π(42² - 35²) = π(1764 - 1225) = π(539) = 1693.46 ≈ 1694 cm². Option A (3850) is close to π×35² which would be the inner circle area. Option C (1925) is close to π×42² which would be the outer circle area. Option D appears to be a miscalculation.

Multiple choice
  1. 220 m2/मी2

  2. 224 m2/मी2

  3. 225 m2/मी2

  4. 230 m2/मी2

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

When a square is inscribed in a circle, the diagonal of the square equals the diameter of the circle. Circle radius = 14 m, so diameter = 28 m = diagonal of square. Side of square = diagonal/√2 = 28/√2 = 14√2 m. Area of square = (14√2)² = 392 m². Area of circle = π×14² = 196π ≈ 616 m². Area outside square = 616 - 392 = 224 m². Option A (220 m²) and D (230 m²) are common approximation errors. Option C (225 m²) is unrelated.

Multiple choice
  1. 16 m/मी

  2. 15 m/मी

  3. 14 m/मी

  4. 12 m/मी

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

For a cylindrical pipe, volume = π(R² - r²)×h where R = outer radius = 8+1 = 9 m, r = inner radius = 8 m, and h = length. Cross-sectional area = π(9² - 8²) = π(81-64) = 17π. Given volume = 748 m³, so h = 748/(17π) = 748/53.41 ≈ 14 m. Option A (16 m) would require different radius values. Option D (12 m) is a common miscalculation error.

Multiple choice
  1. 86 cm2/ सेमी2

  2. 314 cm2/ सेमी2

  3. None of these / इनमें से कोई नही

  4. 78 cm2/ सेमी2

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

When four circles of radius 10cm are drawn at the corners of a 20cm square, each circle is centered at a corner. The area enclosed between the circles equals the square's area minus the area of four quarter-circles (which equals one full circle). Square area = 400 cm², circle area = π(10)² ≈ 314 cm². Enclosed area = 400 - 314 = 86 cm².

Multiple choice
  1. 352 cm2/सेमी2

  2. 296 cm2/सेमी2

  3. 176 cm2/सेमी2

  4. 616 cm2/सेमी2

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

When a rectangle of dimensions 7cm × 4cm is revolved about its length (7cm), it forms a cylinder with height = 7cm and radius = 4cm (the width becomes the radius). Volume = πr²h = π(4)²(7) = 112π cm³. Using π = 22/7: 112 × 22/7 = 16 × 22 = 352 cm³. Note: Option A shows cm² but should be cm³ - this is a unit error.

Multiple choice
  1. 1 cm3/सेमी3

  2. 2 cm3/सेमी3

  3. 3 cm3/सेमी3

  4. 4 cm3/सेमी3

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

Three circles of radius 3.5 cm touch each other. Their centers form an equilateral triangle of side 7 cm. Area enclosed = area of equilateral triangle - 3 × area of 60° sector. Triangle area = (√3/4) × 7² ≈ 21 cm². Each sector area = (60/360) × π × 3.5² ≈ 6.4 cm². Enclosed area = 21 - 3 × 6.4 ≈ 2 cm². Note: units should be cm², not cm³ as written.

Multiple choice
  1. 800

  2. 240

  3. 136

  4. 308

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

For a right pyramid with square base, lateral surface area = perimeter of base × slant height / 2. Slant height l = √(h² + (a/2)²) = √(8² + 6²) = 10m. Lateral area = (4 × 12) × 10 / 2 = 240 m². Option B is correct.

Multiple choice
  1. 24680 sq.cm./ वर्ग मी.

  2. 18384 sq.cm. / वर्ग मी.

  3. 32464 sq.cm./ वर्ग मी.

  4. 28336 sq.cm./ वर्ग मी.

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

Outer curved surface area of a pipe (cylinder) = 2πrh, where r = 28 cm, h = 161 cm. Area = 2 × (22/7) × 28 × 161 = 2 × 22 × 4 × 161 = 176 × 161 = 28336 sq. cm. Option D is correct.

Multiple choice
  1. 7543 cm2/सेमी2

  2. 5146 cm2/सेमी2

  3. 5432 cm2/सेमी2

  4. 7246 cm2/सेमी2

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

For a cone with r = 30 cm and h = 40 cm, slant height l = √(r² + h²) = √(900 + 1600) = 50 cm. Total surface area (sheet needed) = πr(l + r) = π × 30 × 80 = 2400π. Using π = 22/7: 2400 × 22/7 = 7542.85 ≈ 7543 cm².

Multiple choice
  1. 174.4 %

  2. 120.8 %

  3. 54 %

  4. 64.8 %

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

Original volume = (1/3)πr²h. New radius = 1.4r, new height = 1.4h. New volume = (1/3)π(1.4r)²(1.4h) = (1/3)πr²h × 1.4³ = V × 2.744. Increase = 2.744 - 1 = 1.744 = 174.4%. Volume scales with the product of dimension changes.

Multiple choice
  1. 1254 cm2 /सेमी2

  2. 704 cm2 /सेमी2

  3. 550 cm2 /सेमी2

  4. 154 cm2 /सेमी2

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

Cone volume = (1/3)πr²h = 1232. With h = 24, π = 22/7: (1/3)(22/7)r²(24) = 1232. Solving: r² = 49, r = 7. Slant height l = √(h² + r²) = √(576 + 49) = 25. Curved surface = πrl = (22/7) × 7 × 25 = 550 cm².