Mensuration Questions

Multiple choice
  1. $6.4cm$
  2. $5.4cm$
  3. $1.4cm$
  4. $3.4cm$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Volume of tube = pi * (R^2 - r^2) * h = pi * (3.5^2 - 3^2) * 21 = pi * (12.25 - 9) * 21 = pi * 3.25 * 21 = 68.25 * pi. Volume of cone = (1/3) * pi * r^2 * h = (1/3) * pi * r^2 * 7. Setting them equal: 68.25 = (7/3) * r^2. r^2 = 68.25 * 3 / 7 = 29.25. r = sqrt(29.25) approx 5.4.

Multiple choice
  1. $\dfrac {10}{8}cm$
  2. $\dfrac {18}{5}cm$
  3. $\dfrac {10}{9}cm$
  4. $\dfrac {1}{9}cm$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The volume of the sphere is (4/3) * pi * r^3 = (4/3) * pi * (7.5)^3. The water level drop is equal to the volume of the sphere divided by the cross-sectional area of the jar (pi * 12.5^2). Calculation: (4/3 * pi * 7.5^3) / (pi * 12.5^2) = (4/3 * 421.875) / 156.25 = 562.5 / 156.25 = 3.6 cm, which is 18/5 cm.

Multiple choice
  1. $204.3\ \text{ cm }^{ 2 }$(approx)
  2. $102.8\ \text{ cm }^{ 2 }$(approx)
  3. $40.8\ \text{ cm }^{ 2 }$(approx)
  4. $52\ \text{ cm }^{ 2 }$(approx)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Curved surface area of a cone is pi * r * l, where l = sqrt(r^2 + h^2). With r=5 and h=12, l = sqrt(25 + 144) = 13. Area = 3.14 * 5 * 13 = 204.1. Option A is the closest.

Multiple choice
  1. $94.29\, cm^3$
  2. $108.25\, cm^3$
  3. $48.52\, cm^3$
  4. $90.28\, cm^3$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Volume = Volume of hemisphere + Volume of cone. V = (2/3)pi*r^3 + (1/3)*pi*r^2*h. r=3, h=4. V = (1/3)*pi*r^2(2r + h) = (1/3)3.14*9(6+4) = 3*3.14*10 = 94.2 cm^3. The option 94.29 is the closest.

Multiple choice
  1. $660\mathrm { cm } ^ { 2 }$
  2. $930\mathrm { cm } ^ { 2 }$
  3. $1320\mathrm { cm } ^ { 2 }$
  4. $640\mathrm { cm } ^ { 2 }$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Curved surface area of a cylinder = 2 * pi * r * h. Diameter = 21, so radius r = 10.5. Area = 2 * (22/7) * 10.5 * 10 = 2 * 22 * 1.5 * 10 = 660.