Question

A parabolic listening device is shaped such that the depth of the bowl depends on its radius and can be represented by the curve D(r) = 0.145r2.

What is the radius when the depth is 8 inches? Round to the nearest thousandth of an inch.

Answer 1

Answer: A

Step-by-step explanation: Edge2023

Answer 2

`\large \boxed{\text{7.428 in}}`

Explanation:

`\begin{array}{rcl}D & = & 0.145 r^(2)\\8 & = & 0.145 r^(2)\\55.17 & = & r^(2)\\r & = & √(55.17)\\& = & \textbf{7.428 in}\\\end{array}\\\text{The radius is $\large \boxed{\textbf{7.428 in}}$ when the depth is 8 in.}`

The graph shows the profile of your parabolic listening device,