Surface Areas and Volumes
EXERCISE 13.3
Q1: Diameter of the base of a cone is 10.5 cm and its slant height is 10 cm. Find its curved surface area.
Answer: Given r = 10.5/2 = 5.25 cm, l = 10 cm.
Curved surface area (CSA) of the cone = πrl
= (22/7) × 5.25 × 10 = 165 cm² (Answer)
Q2: Find the total surface area of a cone, if its slant height is 21 m and diameter of its base is 24 m.
Answer: Given, l = 21m, r = 24/2 = 12 m
TSA (cone) = πr(l + r)
= (22/7) × 12 (21 + 12)
= 1244.57 m² (Answer)