Hint for 1: The volume of a triangular prism is 0.5*base*perpendicular_height*depth.
Hint for 2: Volume = mass*density where mass is in kg and density is in kg/m^3.
Given you have 0.6 grams per cubic centimeter, this means you have 0.0006 * (100)^3 = 600 kg per cubic metre.
Is this a problem in your mathematics class? Are you doing calculus?