Mathematics is everywhere in our lives and shows its beauty in the form of numbers. The number √2, the Pythagor constant, along with π, e, ϕ is one of the most popular numbers both in mathematics and in our everyday life. The square root of 2 is the first irrational number in the history of mathematics, that is, it cannot be represented as a fraction. The history of this number goes back over 4000 years. A commonly used approximation to √2 is the fraction 99/70.

 

There are many interesting facts that show the beauty of this number. The square root of 2 can be represented as the diagonal of a square with a side of 1.

What should the dimensions of the sheet be so that when the sheet is folded in half the proportions are preserved? For this, the ratio of the long side of the paper to the short side must be equal to the square root of 2. The aspect ratio of the most famous A4 paper format, which measures 297x210, is equal to the square root of 2 (297/210 = √2). All paper formats of the "A", "B", "C" series adhere to this logic.

The square root of 2 has been used since time immemorial to this day in architecture, technology, design, fashion…