To find the area of a square, you use the formula:

$\text{Area} = \text{side}^2$

In this case, the side of the square is given as $5.5 \, \text{mm}$.

$\text{Area} = (5.5 \, \text{mm})^2 = 5.5 \times 5.5 = 30.25 \, \text{mm}^2$

So, the area of the square is:

$30.25 \, \text{mm}^2$

Would you like further details or have any questions?

Here are some related questions:

1. What is the formula for the perimeter of a square?
2. How does the area formula change if the figure is a rectangle?
3. If the side of the square was doubled, what would be the new area?
4. Can the area formula be applied to other polygons? Why or why not?
5. How can you express the side length in different units, like centimeters or meters?

Tip: When solving geometric problems, always remember to keep the units consistent throughout your calculations.