Final Answer:
The length of one side of Joey's model is x inches, option 1.
Step-by-step explanation:
In a square, all sides are equal in length. Therefore, if each side of Joey's model is represented by the variable x, the length of one side is indeed x inches. The correct option is 1) x inches, as it directly corresponds to the variable representing the side length. Options 2) 2x inches, 3) 4x inches, and 4) 8x inches are incorrect in the context of a square model where all sides have equal length. Joey's model follows the basic property of a square, where each side is of the same length, represented by the variable x.
Option A is answer.