The undersurface of a cell is formed bij three congruent rhombusses.[br]The area of the rhombus is defined by its diagonals d and D.

The left graphical shows the prism in a frontally view of the blue side surface. [br]You can rotate the 3D view to view the prism and the surfaces from different points of view.[br]The diagonal D is the hypotenusa of a rectangular triangle with rectangle sides r en 2x.