Answer:
width 2 cm
Step-by-step explanation: INCOMPLETE QUESTION
DIAGRAM IS MISSING
We have just one possibility of such structure
We have one row of 9 squares, each of them having 2 cm length so 9 times 2 is 18 cm and of course the height of the rectangle will be 2 cm. Then squares of 2 x 2 cm² fit in a rectangle of 18 cm length and 2 cm wide.
We can choose a configuration of 9 squares in three equal rows, in that way we get three sides of 6 cm length, and to form a square we need 6 x 3 = 18 cms of height and the surface becomes a square and we lose the initial condition from problem statement " identical squares inside a rectangle"