This is the concept of volume of solid materials, we are required to find the diameter of cone with height 8 and volume 150 m^3.
volume of cone is given by;V=1/3 (pi*r^2*h)
making r^2 the subject we get;
V/(pi*h)=r^2
inserting the values in our formula we get:
150/(pi*8)=r^2
r^2=5.97
thus;
r=sqrt(5.97)=2.44
But ;
diameter=2*radius
thus
diameter=2.44*2
=4.88 m