Question

Surface area and volume exercise 13.3 solution

Answer 1

Assume unless stated otherwise.
1. Diameter of the base of a cone is 10.5 cm and its slant height is 10 cm. Find its curved
surface area and its total surface area.
Ans. Diameter of cone = 10.5 cm
Radius of cone (r) = = cm
Slant height of cone = 10 cm
Curved surface area of cone= = = 165 cm2
2. Find the total surface area of a cone, if its slant height is 21 cm and diameter of the
base is 24 cm.
Ans. Slant height of cone = 21 m
Diameter of cone = 24 m


Radius of cone = = 12 m
Total surface area of cone =
=
= = 1244.57 m2
3. Curved surface area of a cone is 308 cm2 and its slant height is 14 cm. Find (i) radius
of the base and (ii) total surface area of the cone.
Ans. (i) Slant height of cone = 14 cm
Curved surface area of cone = 308 cm2
=πrl=308
=22/7*r*14=308