Question

Can you please help me out with a question

Answer 1

Step 1: Identify the formula to get the surface area(S.A) of a cone

Given values include,

Diameter= 12m

Radius (r)= diameter/2= 12m/2=6m

slant height (l)=9m

The formular is given as thus,

`\begin{gathered} SA=Area\text{ of the circular base +Curved suface area} \\ SA=\pi r^2+\text{ }\pi rl \end{gathered}`

Area of circular base will be

`\begin{gathered} \text{Area of circular base= }\pi r^2 \\ \text{Area of circular base}=\text{ }\pi*6^2 \\ \text{Area of circular base=36}\pi m^2 \\ \text{leaving in terms of }\pi \\ \end{gathered}`

curved surface area will be

`\begin{gathered} \text{Curved sureface Area=}\pi rl \\ \text{curved surface area=}\pi*6m*9m \\ \text{curved surface area=54}\pi m^2 \\ \text{Leaving in terms of }\pi \end{gathered}`

Therefore,

The surface area of the cone will be

`\begin{gathered} SA=36\pi m^2+54\pi m^2 \\ SA=90\pi m^2 \end{gathered}`

Hence,

The surface area of the right cone= 90πm²

Therefore the correct answer is option A