NCERT Class 9 Solutions: Surface Areas and Volumes (Chapter 13) Exercise 13.2 – Part 2

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Different types of shapes also its volume and total surface …

Different Types of Shapes

Q-4 The diameter of a roller is and its length is. It takes complete revolutions to move once over to level a playground. Find the area of the playground in.Solution:

  • The roller length is (h)

  • The cylinder radius is

  • Total no. of revolutions

    • Distance covered by roller in one revolution

  • Area of the playground

  • ( complete revolutions to level a playground)

Q-5 A cylindrical pillar is in diameter and in height. Find the cost of painting the curved surface of the pillar at the rate of.Solution:

  • The pillar radius

  • The pillar height

  • Painting rate

    • Curved surface

    • Total cost of painting

      • (Painting rate )

Q-6 Curved surface area of a right circular cylinder is. If the radius of the base of the cylinder is, find its height.Solution:

  • The radius of the base r and the height of the cylinder h.

  • Area of a right circular cylinder is

Curved surface area

Q-7 The inner diameter of a circular well is. It is deep. Find

  1. Its inner curved surface area,

  2. The cost of plastering this curved surface at the rate of


Circular well radius The well depth Plastering rate

  • Curved surface

  • Cost of plastering =

Q-8 In a hot water heating system, there is a cylindrical pipe of length and diameter. Find the total radiating surface in the system.Solution:

Formulas for surface area and volume of a cylinder

Surface Area and Volume of a Cylinder

  • The pipe radius

  • The pipe length

Total radial surface or curved surface area of the pipe