Mensuration Questions

Multiple choice
  1. $\displaystyle 115.5cm^{2}$
  2. $\displaystyle 151.5cm^{2}$
  3. $\displaystyle 155cm^{2}$
  4. $\displaystyle 151cm^{2}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A sphere cut in half creates two hemispheres. Each hemisphere has a curved surface area (2 * pi * r^2) and a flat circular base (pi * r^2). Total surface area = 3 * pi * r^2. r = 3.5. Area = 3 * (22/7) * 3.5 * 3.5 = 3 * 22 * 0.5 * 3.5 = 115.5.

Multiple choice
  1. 6 m

  2. 6.5 m

  3. 6.7 m

  4. 6.8 m

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

Curved surface area (CSA) = 2 * pi * r * h = 264. Volume (V) = pi * r^2 * h = 924. Dividing V by CSA: (pi * r^2 * h) / (2 * pi * r * h) = 924 / 264. This simplifies to r / 2 = 3.5, so r = 7. Substitute r = 7 into CSA: 2 * (22/7) * 7 * h = 264, so 44 * h = 264, h = 6.

Multiple choice
  1. 1 : 2 : 3

  2. 3 : 2 : 1

  3. 2 : 1 : 3

  4. 1 : 3 : 2

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

Cone: (1/3) * pi * r^2 * h = (1/3) * pi * 1^2 * 1 = pi/3. Cylinder: pi * r^2 * h = pi * 1^2 * 1 = pi. Hemisphere: (2/3) * pi * r^3 = (2/3) * pi * 1^3 = 2pi/3. Ratio: pi/3 : pi : 2pi/3 = 1 : 3 : 2.

Multiple choice
  1. $ \displaystyle (\sqrt{2}+1):3:4 $
  2. $ \displaystyle (\sqrt{3}+1):3:4 $
  3. $ \displaystyle \sqrt{2}:3:4 $
  4. $ \displaystyle \sqrt{3}:7:8 $
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

With radius r as the common height, the cone's whole surface area is (sqrt(2) + 1)pi r^2. The hemisphere and cylinder have whole surface areas 3pi r^2 and 4pi r^2, respectively. Their ratio is therefore (sqrt(2) + 1) : 3 : 4.

Multiple choice
  1. $ \displaystyle \frac{4}{3}\times (5\pi )cm^{3} $
  2. $ \displaystyle \frac{4}{3} \pi cm^{3} $
  3. $ \displaystyle 5\pi cm^{3} $
  4. $ \displaystyle \frac{10\pi }{3}cm^{3} $
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The greatest sphere that can be cut from a cylinder of radius 1 cm and height 5 cm is limited by the radius. The sphere's radius is 1 cm. Volume = (4/3) * pi * r^3 = (4/3) * pi * 1^3 = (4/3) * pi.

Multiple choice
  1. $ \displaystyle 190 \pi cm^{2} $
  2. $ \displaystyle 192 \pi cm^{2} $
  3. $ \displaystyle 195 \pi cm^{2} $
  4. $ \displaystyle 198 \pi cm^{2} $
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Surface area = Cylinder lateral area + Base area + Cone lateral area. Cylinder lateral = 2 * pi * r * h = 2 * pi * 6 * 8 = 96 pi. Base = pi * r^2 = 36 pi. Cone lateral = pi * r * l, where l = sqrt(r^2 + h^2) = 10. Cone lateral = pi * 6 * 10 = 60 pi. Total = 96 pi + 36 pi + 60 pi = 192 pi.

Multiple choice
  1. $ \displaystyle 2\pi r^{2} $
  2. $ \displaystyle \pi r^{2} $
  3. $ \displaystyle 3\pi r^{2} $
  4. $ \displaystyle 4\pi r^{2} $
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A hemisphere has a curved surface area of 2*pi*r^2 and a flat circular base of pi*r^2. Total surface area = 3*pi*r^2.

Multiple choice
  1. $ \displaystyle \frac{1000}{3}\pi cm^{3} $
  2. $ \displaystyle \frac{500}{3}\pi cm^{3} $
  3. $ \displaystyle \frac{250}{3}\pi cm^{3} $
  4. $ \displaystyle \frac{125}{3}\pi cm^{3} $
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The cone is cut at the midpoint of the height. The smaller cone has height 5 and radius 5 (by similar triangles). Volume = (1/3) * pi * r^2 * h = (1/3) * pi * 5^2 * 5 = 125/3 * pi.