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

diameter=24 ...... radius =24/2==12
height =21
formula
$\pi \: r \: ( \: r + l)$

$\pi \: 12(12 + 21)$
$396\pi$

Answer 2

hlo frd here is your ans
the diameter of the base of cone is 24m
slant hight = 21 m
total surface area of a cone = ( π r l+ π r^2)
so r = 24/ 2= 12 m
and l =√h^2+r^2
= √ 21^2+12^2
= √441+144
= √585=24.18m
so total surface area = ( 3.14 × 12× 24.18 + 3.14 × 12^2)
(911.1+ 452.16)
1,363.26 m ^2 is the ans