Answer:
Option D. [tex]7.1\ m[/tex]
Step-by-step explanation:
we know that
The area of a circle is equal to
[tex]A=\pi r^{2}[/tex]
In this problem we have
[tex]A=40\ m^{2}[/tex]
substitute and solve for r
[tex]40=\pi r^{2}[/tex]
[tex]r^{2}=40/( \pi)[/tex]
[tex]r=3.57\ m[/tex]
Multiply the radius by [tex]2[/tex] to obtain the diameter
so
[tex]3.57*2=7.14\ m[/tex]
