Question

The curved surface area of cone is 528 sq cm. If slant height of cone is 21cm, then radius of the base is​

Answer 1

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$\huge{\underline{\underline{\sf{\blue{SOLUTION:-}}}}}$

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$\sf{\underline{\green{AnswEr:-}}}$

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• The radius of the base = 16 Cm

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$\sf{\underline{\green{Given:-}}}$

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• The curved surface area of cone is 528 sq cm. If slant height of cone is 21cm.

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$\sf{\underline{\green{Find:-}}}$

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• The radius of the base = ?

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$\sf{\underline{\green{Explanation:-}}}$

$\sf{\underline\purple{Formula\:Used\:Here:-}}$

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$\bigstar\boxed{\sf{\red{C.A.S \: of \: cone = \pi rl}}}$

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$\sf{\underline{\pink{Putting\:the\:values:-}}}$

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$\longrightarrow \sf {\dfrac{22}{7} \times Radius \times 21 = 528}$

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$\longrightarrow \sf {22 \times Radius \times 3 = 528}$

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$\longrightarrow \sf {Radius = \dfrac{528}{22 \times 3} }$

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$\longrightarrow \sf {Radius = \dfrac{528}{66}}$

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$\longrightarrow \sf {Radius = \dfrac{176}{11} }$

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$\longrightarrow \sf {Radius = 16}$

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$\:\:\:\:\dag\bf{\underline{\underline \red{Hence:-}}}$

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• The radius of the base is 16 Cm.

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$\rule{200}{2}$

Answer 2

⚘ Given :-

• C.S.A. Of Cone = 528cm²

• Slant height = 21cm.

⚘ To Find :-

• The radius of the base.

⚘ Solution :-

We know that,

$\Large\boxed{\sf{C.S.A \: of \: Cone \: = \: \red{\pi rl}}}$

Put the values.

⇢ $\rm{\dfrac{22}{\cancel{7}} \times r \times {\cancel{21}} \: \: ^ {3} = 528}$

⇢ $\rm{66r = 528}$

⇢ $\rm{r = \dfrac{528}{66} }$

⇢ $\underline{\boxed{\rm{r = \blue{8cm}}}}$

Hence, Radius Of Base = 8cm.