Mensuration Questions

Multiple choice
  1. 2.5 cm

  2. 2.7 cm

  3. 2.1 cm

  4. 2 cm

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

Volume of cone = 1/3 * pi * r^2 * h. V1 = 1/3 * pi * 2.1^2 * 4.1. V2 = 1/3 * pi * 2.1^2 * 4.3. Total V = 1/3 * pi * 2.1^2 * (4.1 + 4.3) = 1/3 * pi * 2.1^2 * 8.4. Sphere volume = 4/3 * pi * R^3. 4/3 * pi * R^3 = 1/3 * pi * 2.1^2 * 8.4. 4R^3 = 2.1^2 * 8.4. R^3 = 2.1^2 * 2.1 = 2.1^3. R = 2.1.

Multiple choice
  1. 15400 cm$\displaystyle ^{2}$
  2. 1540 cm$\displaystyle ^{2}$
  3. 154 cm$\displaystyle ^{2}$
  4. 15.400 cm$\displaystyle ^{2}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The surface area of a sphere is given by 4 * pi * r^2. Using r = 35 and pi = 22/7, the area is 4 * (22/7) * 35 * 35 = 4 * 22 * 5 * 35 = 15400 cm^2.

Multiple choice
  1. $17600$ $cm^3$
  2. $16600$ $cm^3$
  3. $156600$ $m^3$
  4. None of these

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

Rolling a paper of width 14cm along its width means the height of the cylinder is 14cm. The circumference of the base is the length of the paper, but here the radius is given as 20cm. Volume = pi * r^2 * h = 3.14 * 20^2 * 14 = 3.14 * 400 * 14 = 17584, which is approximately 17600.

Multiple choice
  1. $2\pi r^2$
  2. $2\pi rh^2$
  3. $2\pi rh$
  4. None

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

The lateral surface area of a cylinder is the circumference of the base multiplied by the height, which is 2 * pi * r * h.

Multiple choice
  1. 2 $\times$ area of rectangle $+$ area of circle
  2. 2 $\times$ area of circle $+$ area of rectangle
  3. 2 $\times$ area of square $+$ area of rectangle
  4. 2 $\times$ area of rectangle $+$ area of rectangle
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The total surface area of a cylinder consists of two circular bases (2 * area of circle) and the curved lateral surface, which unfolds into a rectangle (area of rectangle).

Multiple choice
  1. $1223\ cm^{3}$
  2. $1979\ cm^{3}$
  3. $1323\ cm^{3}$
  4. $1332\ cm^{3}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

At 5 paise per cm^2, a cost of Rs 35.20 corresponds to a curved surface area of 704 cm^2. Using pi r l = 704 with l = 25 cm gives r = 8.96 cm. The height is about 23.35 cm, and V = (1/3)pi r^2h is approximately 1979 cm^3.

Multiple choice
  1. $98.56$ cm$^2$
  2. $68.56$ cm$^2$
  3. $38.56$ cm$^2$
  4. None of these

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

The surface area of a sphere is given by 4 * pi * r^2. Using r = 2.8 and pi = 22/7, the calculation is 4 * (22/7) * 2.8 * 2.8 = 4 * 22 * 0.4 * 2.8 = 98.56 cm^2.