NCERT Class 9 Solutions: Surface Areas and Volumes (Chapter 13) Exercise 13.8 – Part 2
Q4 The diameter of the moon is approximately onefourth of the diameter of the earth. What fraction of the volume of the earth is the volume of the moon?
Solution:
If the diameter is oneforth then radius of moon would also be onefourth 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.
Q5 How many liters of milk can a hemispherical bowl of diameter hold?
Solution:
Given,

Diameter of a hemispherical bowl

Radius(r)
Volume of the hemispherical bowl is



(Since 1 liter = 1000 cubic centimeters)

Q6 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.
Solution:
Given a hemispherical tank with some thinkness,

Internal radius

External radius
Volume of iron used = External volume – Internal volume