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

The correct 7.428 inches

Explanation:

Given the equation is D(r) = 0.145r^2

Where D is the depth and r is the radius
Putting D = 8 inches in the equation

8 = 55.2

r^2= 8/ 0.145

r^2 = 55.2

R^2= 7.428 inches

The radius of depth is 7.428 inche

Hope this help you : )

The first option would be correct if it were one half and not one