A triangular prism is 1/2 the volume of a rectangular prism with the same dimensions. V = BH (Base x Width) of a triangular its 1/2BHThe base is 10 x 5, 50 is the base.The height is 6, and that would be 300 / 2 since it's triangular so its 150 inches squared for one. Since there are 2.The total volume is 300 inches squared.