NCERT Class 9 Solutions: Surface Areas and Volumes (Chapter 13) Exercise 13.8 – Part 2 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Volume Formula, Sphere Volume = 4/3 Πr ^ 3, Hemisphere = 2/3 Πr ^ 3

Q-4 The diameter of the moon is approximately one-fourth of the diameter of the earth. What fraction of the volume of the earth is the volume of the moon?


If the diameter is one-forth then radius of moon would also be one-fourth of the radius of the earth.

Let radius of the moon be , then radius of the earth

Volume of the moon

Volume of the earth

Or that is, the volume of the moon is of the volume of the earth.

Q-5 How many liters of milk can a hemispherical bowl of diameter hold?



  • Diameter of a hemispherical bowl
  • Radius (r)

Volume of the hemispherical bowl is

  • (Since 1 liter = 1000 cubic centimeters)

Q-6 A hemispherical tank is made up of an iron sheet thick. If the inner radius is , then find the volume of the iron used to make the tank.


Given a hemispherical tank with some thinkness,

  • Internal radius
  • External radius

Volume of iron used = External volume – Internal volume