Question

Hi there!

Find the tsa of the cone, if it's slant height is 21m diameter of its base is 24m.
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Thanks! :D
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Answer 1

GIVEN :

• Slant height of cone = 21m

• And diameter of its base = 24 m

• So, the radius = 24/2 = 12 m

TO FIND :

• The total surface area of the cone = ?

SOLUTION :

★ TSA of cone = πr (r + l)

➨ TSA of cone = 22/7 × 12 × (12 + 21)

➨ TSA of cone = 22/7 × 12 × 33

➨ TSA of cone = 22/7 × 396

➨ TSA of cone = 1244.57 m²

Hence, the total surface area of cone is 1244.57 m².

$\rule{200}3$

$\boxed{\begin{minipage}{6 cm}\bigstar \:\underline{\textbf{Formulae Related to Cone :}}\\\\\sf {\textcircled{\footnotesize\textsf{1}}} \:Area\:of\:Base =\pi r^2 \\\\ \sf {\textcircled{\footnotesize\textsf{2}}} \:\:CSA = \pi rl\\\\\sf{\textcircled{\footnotesize\textsf{3}}} \:\:TSA = Area\:of\:Base + CSA\\{\quad\:\:\:\qquad=\pi r^2+\pi rl}\\ \\{\textcircled{\footnotesize\textsf{4}}} \: \:Volume=\dfrac{1}{3}\pi r^2h\end{minipage}}$

$\rule{200}3$

Answer 2

GivEn:-

• Slant height of cone (l) = 21m

• Diameter of cone(d) = 24m

To find:-

• Total surface area of cone.

SoluTion:-

GivEn that,

Diameter of cone (d) = 24m

Therefore, Radius of cone (r) = $\sf \dfrac{24}{2} = 12$

As we know that,

$\maltese\;\sf{\underline{\boxed{\bf{\pink{TSA\;of\;Cone = \pi r(l + r)}}}}}$

$:\implies\sf \dfrac{22}{7} \times 12(21 + 12)$

$:\implies\sf \dfrac{22}{7} \times 12(33)$

$:\implies\sf \dfrac{22}{7} \times 396$

$:\implies{\underline{\boxed{\bf{\blue{1244.57\;m^2}}}}}$

$\dag$ Hence, The total surface area of the cone is 1244.57m²

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