Question

The net of a cone is shown below. What is the surface area of the cone rounded to the nearest tenth of a square inch? Use π = 3.14.A. 125.6 in²B. 1,256.6 in²C. 175.8 in²D. 251.3 in²

Answer 1

`(C)175.8in^2`

Step-by-step explanation

The surface area of a cone can be found using the formula:

`A=\pi r^2+\pi rl`

where l = slant height

r = radius

The diameter of the cone is given, but we can find the radius since the radius is half the diameter:

`\begin{gathered} r=(D)/(2) \\ r=(8)/(2) \\ r=4\text{ units} \end{gathered}`

From the figure, the slant height of the cone is 10 units.

Hence, its surface area is:

`\begin{gathered} A=(\pi\cdot4^2)+(\pi\cdot4\cdot10) \\ A=50.24+125.6 \\ A\approx175.8in^2 \end{gathered}`

The answer is option C.