Question

Find the total surface area of the cone. Use the r button on your calculator. altitude = 13 cm, diameter = 11 cm, slant height = 15 cm

Answer 1

In general, the area of a cone is given by the formula below

`\begin{gathered} A=\pi r^2+\pi rl \\ r\rightarrow\text{ radius} \\ l\rightarrow\text{ slant height} \end{gathered}`

Therefore, in our case,

`\begin{gathered} r=(11)/(2)=5.5 \\ l=15 \\ \Rightarrow A=\pi *5.5^2+\pi *5.5*15 \\ \Rightarrow A=112.75\pi \end{gathered}`

Rounding to two decimal places,

`\Rightarrow A\approx354.22`

The answer is approximately 354.22 cm^, option D.