★ Question: The area of a square is 324 square inches. What is the length of one side of the square?
The formula for finding area of squares is:

Squares have 4 sides, and all sides measure the same. If the area is 324 square units, that means the length and width are the same.

x squared(x²) is equal to 324. To find x, you have to do the opposite of squaring, which is finding the square root.

To find x, you have find the square root of 324.

The length of one side is 18 inches
Check:
The formula for finding area is:

The length and width gotten was 18. Put that into the formula:

Multiply:

That means the answer is correct. Your answer is 18 inches.
If you have any questions, feel free to ask in the comments! :)