



 
Chassity, Let's look for the correct expression first. I know that the volume of a cone with base radius r units and height h units is given by
and I know that the circumference of a circle of radius r units is given by
Solving this last equation for r and substituting in the volume expression I get the volume as
Since you want the volume in cubic yards I would convert the measurements to yards. There are 3 feet in a yard so 120 feet is 120/3 = 40 yards and 20 feet is 20/3 = 6.67 yards. Hence the volume of the gravel pile is approximately
Penny  


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences. 