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Question
Find the total surface area of a cone, if its slant height is 21 m and diameter of its base is 24 m.
Solution
Given that,
Radius of base of cone =` (24/2)` = 12 m
The slant height of the cone = 21 m.
Total surface area of cone = πr2 + πrl
= πr (r + l)
= `22/7xx12xx(12+21) m^2`
= `22/7 xx 12 xx 33 m^2`
= `8712/7 m^2`
= `1244.57 m^2`.
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