Final answer:
The area of a square with a side length of (x+55) units is x² + 110x + 3025 square units.
Step-by-step explanation:
If a square has a side length of (x+55) units, to calculate the area of the square, we use the formula for the area of a square, which is the side length squared. Therefore, the area A of the square is (x+55) · (x+55), which simplifies to x² + 110x + 3025 square units.