# MATHEMATICS BEHIND A4 PAPER by Dr Khin Maung Win (Math)

MATHEMATICS 3
MATHEMATICS BEHIND A  4 PAPER
by Dr. Khin Maung Win.Maths.

Everyone is familiar with A 4 size paper. A writing paper of that size measures about 8.3
inches and 11.7 inches, approximately. I say approximately because you can never express the length and breath of a paper of that size by means of fractions or ending decimals.

However, it is not the measurement of the paper of A 4 size that is important,but what is more important is the following property , namely that ”No matter how many times you fold a paper of A 4 size in half lengthwise, i.e. on the longer side, the ratio of the length to the breath remains the same.”

Anyone who has a head for equations can work out that the ratio of length to breath is always square root of two.Quite surprising, I heard that information for the first time from a certain English professor who could only say that the ratio remains the same,about 1.4 but did not know the exact value or did not care to know.He said that papers of other sizes like fool scap or quarto do not have that property.

Again , anyone who has a head for geometry can work out that the length of the A 4 size paper and two breaths of such a paper can form an isosceles right angled triangle as shown here.

The numbers show that the ratio of length to breath of the A 4 size paper is square root of two which can be worked out by Pythagoras theorem.

Reference
Dr. Khin Maung Win . They come in all sizes.
The Working People’s Daily. 6 September. 1987 .