In more advanced math the formula would be written as A S2 or area equals side squared. Examples of calculating the area of a rectangle. The area of a parallelogram is found using this formula.
It could be a 1 foot by 1 foot square but then we can use that to actually measure the area of things.
Here the Greek letter p represents a constant approximately equal to 314159 which is equal to the ratio of the circumference of any circle to its diameter. The purple figure had twice the area-- its 10 square units-- as the blue figure. The length of a figure is the distance from left to right. The rectangle above has an area of 15 square units.