Question

Find the total surface area of a cone, if its slant height is 21 m and diameter of its base is 24 m.

Answer 1

Total surface area of a cone

= πr(r+l)

= π(12)(12+21)

= 12π(33)

= 396π

= 396(3.14)

= 1243.44

Hence, the answer is 1243.44m²

Answer 2

Answer: The total surface area the cone is 1244.57 m²

Step-by-step explanation:

Given : slant height of cone ;l = 21m

Diameter of cone = 24m

therefore radius ; r= 12 m

as we know the total surface area of a cone is

$T.S.A.= \pi r (l+r) = \dfrac{22}{7} \times 12( 21+12)= 1244.57 m^2$

Hence, the total surface area the cone is 1244.57 m²