Emily wants to make a rectangular model with a height of one cube she wants to make the model in exactly 2 different ways. how many connecting cubes could emily use to make the model in only two ways.

Three cubes

Step-by-step explanation:

The cubes have to be indistinguishable and all orientations of one cube are also have to be indistinguishable.

All ways of connecting two cubes result in the same shape. So answer is larger than two.

After connecting two cubes, there are ten faces where the third cube can be attached, and two faces which are connected, accounting for all 12 faces of two cubes.

Of the 10 exposed faces, exactly two are on opposite ends, both leading to the same straight line figure. The other 8 faces all lead to an L shape, and all L shapes can be rotated to be identical.

Hence, three cubes can only make a straight shape or an angled shape.

Four cubes can make a straight shape, a L shape, a Γ shape (but flipping it over through 3 dimensions makes L and Γ identical), a T shape, and a square shape. That is either four or five different objects depending on if they can be lifted from the table. Anyway, it is more than two.