



 
Hi Kathleen, You need to know the density of the specific material. You can get some information on the web. For example I typed What is the density of topsoil in pounds per cubic foot? into the Google search window and got a number of responses, one of which said
One ton is 2,000 pounds which is a little less than twice 1,080 pounds and hence a ton of topsoil is almost 2 cubic yards. To be more precise one ton of topsoil is $\large \frac{2000}{1080} \normalsize = 1.85$ cubic yards. You should do something similar for your three materials. You will likely find a range of densities, depending in particular on the moisture content but you should get an idea of the conversions. I hope this helps, 



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