# NCERT Mathematics Class 9 Exemplar Ch 13 Surface Areas and Volumes Part 5

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**Exercise 13.4**

Q.1. A cylindrical tube opened at both the ends is made of iron sheet which is thick. If the outer diameter is and its length is , find how many cubic centimeters of iron has been used in making the tube ?

Answer:

Q.2. A semi-circular sheet of metal of diameter is bent to form an open conical cup. Find the capacity of the cup.

Answer:

Q.3. A cloth having an area of is shaped into the form of a conical tent of radius 5 m

(i) How many students can sit in the tent if a student, on an average, occupies on the ground?

(ii) Find the volume of the cone.

Answer:

Q.4. The water for a factory is stored in a hemispherical tank whose internal diameter is. The tank contains 50 kiloliters of water. Water is pumped into the tank to fill to its capacity. Calculate the volume of water pumped into the tank.

Answer:

Q.5. The volumes of the two spheres are in the ratio. Find the ratio of their surface areas.

Answer:

Q.6. A cube of side 4 cm contains a sphere touching its sides. Find the volume of the gap in between.

Answer:

Q.7. A sphere and a right circular cylinder of the same radius have equal volumes. By what percentage does the diameter of the cylinder exceed its height?

Answer:

Q.8. 30 circular plates, each of radius and thickness 3cm are placed one above another to form a cylindrical solid. Find:

(i) The total surface area

(ii) Volume of the cylinder so formed.

Answer: (i) (ii)