The height of the solid cone is 12cm and the area of the base is 81 π sqcm , find the curved surface area of the cone.[Take π =3.14]
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The height of the solid cone is 12cm and the area of the base is 81 π sqcm , find the curved surface area of the cone.[Take π =3.14]
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Answer:
[tex] \sf \: area = {81cm}^{2} [/tex]
[tex] \implies \: \cancel\pi {r}^{2} = {81} \cancel\pi \\ \\ {r}^{2} = 81 \\ \\ r = \sqrt{9 \times 9} \\ \\ = 9cm[/tex]
So,
[tex] {l}^{2} = {r}^{2} + {h}^{2} \\ \\ \implies \: l = \sqrt{81 + 144} \\ \\ l = \sqrt{225} \\ \\ \boxed { \blue{l = 15cm}}[/tex]
We will use curve surface area of cone
[tex]c.s.a = \pi rl \\ \\ \implies \: 3.14 \times 9 \times 15 \\ \\ = 28.26 \times 15 \\ \\ \green{\boxed{ \sf \large \blue{= 423.9 {cm}^{2} }}}[/tex]
Hope it helps you from my side :)
Answer:
Curved surface area of cone = 3.14 × 9 × 15 = 423.9cm^2.
[tex]thanks[/tex]