To find the area of a square, you need to know the length of one of its sides. Let's say the length of one side is 5 units. To find the area, you would simply multiply the length of the side by itself, like so:
Area = side x side
Area = 5 x 5
Area = 25 square units
So the area of a square with a side length of 5 units is 25 square units.