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Question is in image. The cone at the top is part of the question

Question is in image. The cone at the top is part of the question-example-1
User Barin
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1 Answer

4 votes

The formula to calculate the surface area of a cone is given by


SA=pi*r^2+pi*r*l

where

r=16/2=8 in ----> the radius is half the diameter

l=18 in ----> slant height

substitute given values


\begin{gathered} SA=pi*8^2+pi*8*18 \\ SA=64pi+144pi \\ SA=208pi\text{ in}^2 \end{gathered}

The surface area is 208pi square inches

Problem N 9

Find out the height of the cone

Applying the Pythagorean Theorem


\begin{gathered} l^2=h^2+r^2 \\ 18^2=h^2+8^2 \\ h^2=18^2-8^2 \\ h^2=260 \\ h=√(260) \\ h=16.1\text{ in} \end{gathered}

The answer is option B

User Tjw
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