NCERT Class 9 Solutions: Surface Areas and Volumes (Chapter 13) Exercise 13.3 – Part 1
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Q1 Diameter of the base of a cone is and its slant height is . Find its curved surface area.Solution:
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

=

=

=
Q2 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
Q3 Curved surface area of a cone is and its slant height is. Find

Radius of the base and

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