The cube will be smallest if AB is an edge rather than a diagonal. The distance from A to B is found by the distance formula in 3-dimensions: d =d = d = d = d = d = 25 So each edge of the cube will be 25, and the volume is given by the formula: V = E³ where E is the length of an edge, or V = (25)³ = 15625 cubic units. Edwin