How to calculate the average number of columns for a specific surface area? is that true we divide the area by 12?

A rectangle is a quadrangle, or a parallelogram, take the coulmn as an example where all four of its angles are right angles, or the diagonals have the same length. If l = w is true, then the rectangle is called a square, and then we have the following formulas: d = l√2, l = d÷√2 and S = l² = d²/2.Note: A measurement unit selection is optional

Rectangle Area :  S = l × w

Angle: α = arctan(w ⁄ l)

Angle: β = arctan(l ⁄ w)

Perimeter: p =2 × (l+w)

Diagonal : d = √l²+w²

not ture to be divided by12