b'Metal Volume ContainersWith the Metal Volume Containers, the child discovers the rules for the calculation of volume. The 3 hollow geometric forms have the same base. The large rectangular prism and the pyramid have the same height, and the small rectangular prism is 1/3 of that height.Item Number: 012800$249.95Elementary Geometric SolidsA set of blue geometric solids used for the calculation of volume. The solids are derived from a base of 10 x 10 cm and a height of 20 cm. Each sold individually.Square Based Prism Rhombic Based Prism Triangular Based PrismItem Number: 018801 Item Number: 018802 Item Number: 018803$79.95 $114.95 $84.95 Divided 2 Triangular Based Prisms Hexagonal Based Prism Hexagonal Based PrismItem Number: 018804 Item Number: 018805 Item Number: 018806$109.95 $84.95 $109.9592'