Volume of a cone is given by;
[tex]V=\frac{1}{3}\pi r^2h[/tex]where v is the volume, r is the radius and h is the height
From the diagram;
h = 4 r=3 and π=3.14
substitute the values into the formula
[tex]V=\frac{1}{3}\times3.14\times3^2\times4[/tex][tex]=\frac{113.04}{3}[/tex][tex]\approx37.7ft^3[/tex]