Find the total surface area of a cone, if its slant height is 21 m and diameter of its base is 24 m.
Radius (r) = 24/2 m = 12 m
Slant height (l) = 21 m
Total surface area of the cone = πr (l + r) m2
= 22/7 × 12 × (21 + 12) m2
= (22/7 × 12 × 33) m2
= 1244.57 m2
