Class 9 – Surface areas and Volumes

Example 10: A capsule of medicine is in the shape of a sphere of diameter 3.5 mm. How much medicine (in mm3) is needed to fill this capsule? Question 9 Class 9 | Home

Example 9: Twenty seven solid iron spheres, each of radius r and surface area S are melted to form a sphere with surface area S′. Find the (i) radius r ′ of the new sphere, (ii) ratio of S and…

Example 8: A dome of a building is in the form of a hemisphere. From inside, it was white-washed at the cost of  Rs. 4989.60. If the cost of white-washing is Rs. 20 per square metre, find the (i) inside…

Example 7: Find the volume of a sphere whose surface area is 154 cm2. Question 6 Question 8

Example 6: A hemispherical tank is made up of an iron sheet 1 cm thick. If the inner radius is 1 m, then find the volume of the iron used to make the tank. Question 5 Question 7

Example 5: How many litres of milk can a hemispherical bowl of diameter 10.5 cm hold? Question 4 Question 6

Example 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? Question 3 Question 5

Example 3: The diameter of a metallic ball is 4.2 cm. What is the mass of the ball, if the density of the metal is 8.9 g per cm3? Question 2 Question 4

Example 2: Find the amount of water displaced by a solid spherical ball of diameter (i) 28 cm (ii) 0.21 m Question 1 Question 3