NCERT Class 9 Solutions: Surface Areas and Volumes (Chapter 13) Exercise 13.3 – Part 1 (For CBSE, ICSE, IAS, NET, NRA 2022)

Get unlimited access to the best preparation resource for CBSE/Class-9 : get questions, notes, tests, video lectures and more- for all subjects of CBSE/Class-9.

Q-1 Diameter of the base of a cone is and its slant height is . Find its curved surface area. Solution:

Lateral and Total Surface Area of the Cone

Cone has a slant height s which is given as (because of Pythagoras theorem) .

Here, cone radius (r) and slant height (l) . Therefore, curved surface area of the cone

  • =
  • =

Q-2 Find the total surface area of a cone, if its slant height is and diameter of its base is . Solution:

  • Radius (r)
  • Slant height (l)

Total surface area of the cone

Q-3 Curved surface area of a cone is and its slant height is . Find

  1. Radius of the base and
  2. Total surface area of the cone.

Solution:

Solution (I)

Curved surface of a cone and slant height (l)

Therefore,

Solution (II)

Therefore, total surface area of the cone

Developed by: