Question

what is the surface area of this cone? round your answer to the nearest hundredth. 12.3 ft 9.8 ft square feet submit

Explanation:

Step1: Identify radius and slant height

The diameter is 9.8 ft, so the radius $r=\frac{9.8}{2}=4.9$ ft, and the slant height $l = 12.3$ ft.

Step2: Recall surface - area formula

The surface - area formula of a cone is $A=\pi r(r + l)$.

Step3: Substitute values

$A=\pi\times4.9\times(4.9 + 12.3)$.
First, calculate the sum inside the parentheses: $4.9+12.3 = 17.2$.
Then, $A=\pi\times4.9\times17.2$.
$A = 4.9\times17.2\times\pi=84.28\pi$.

Step4: Calculate the value

Using $\pi\approx3.14159$, $A\approx84.28\times3.14159\approx264.72$ square feet.

Answer:

$264.72$