It is given that the area of the circle is
[tex]4\pi sqft[/tex]The area of the circle is given by:
[tex]A=\pi\ast r^2=\pi\ast(\frac{D^2}{4})[/tex]Substitute the area to get:
[tex]\begin{gathered} 4\pi=\pi\ast(\frac{D^2}{4}) \\ 16=D^2 \\ D=4 \end{gathered}[/tex]Hence the diameter of the circle is 4 feet.
