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The radius of a cone is 3 cm and the surface area is 81pi cm squared. Find the slant height of this cone.

User Kylar
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1 Answer

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24cm

1) We can find out the slant height of that cone by making use of the following:


\begin{gathered} R=3 \\ A=\pi r\mleft(s+r\mright) \\ \end{gathered}

2) Plugging into that we can write out:


\begin{gathered} 81\pi=3\pi(s+3) \\ (81\pi)/(3\pi)=(3\pi(s+3))/(3\pi) \\ 27=s+3 \\ 27-3=s \\ s=24 \end{gathered}

Hence, the slant height is 24 cm

User Dmitriif
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