# Pi

### 204 decimal places

The number π to 204 decimal places is: 3, 141592 653589 793238 462643 383279 502884 197169 399375 105820 974944 592307 816406 286208 998628 034825 342117 067982 148086 513282 306647 093844 609550 582231 725359 408128 481117 450284 102701 938521 105559 644622 948954 930381 964428. ^{1)}

### Pi day

March 14 is the informal celebration of the number π. The day is also linked to the date of Albert Einstein's birth, which is why it is celebrated in many schools and universities. ^{2)}

### Pi pie

In Anglo-Saxon countries, there is even a tradition of preparing a “Pi pie” on Pi day. ^{3)}

### William Jones

The symbol π was introduced by Welsh mathematician William Jones in 1706, in his monograph “Synopsis palmariorum mathesos.” ^{4)}

### περίμετρον

The symbol is the first letter of the Greek word περίμετρον - perimetron, which means circumference. ^{5)}

### Euler

The number Pi was popularized by Leonhard Euler. ^{6)}

### Non-measurable number

The number π is a non-measurable number, which means that it cannot be represented as the quotient of two integers.
^{7)}

### Ancient times

The number π already had its uses in ancient times, when during practical activities such as agriculture and construction, people noticed that the ratio of a circle's circumference to its diameter was a constant value. ^{8)}

### Quadrature of a circle

The quadrature of a circle is an unsolved problem related to the number π. It involves plotting a square with the same area as the circle. In 1897, Edward J. Goodwin - a doctor from Indiana - claimed to have accomplished this, but it was eventually found that in the figures he plotted, the number π was 3, 2. The enterprising doctor quickly reserved his method and later made it available for use by the state of Indiana. ^{9)}

### π in the Bible

The number π is mentioned in the Bible in one of its approximations - 3:1 - precisely in the Second Book of Kings, Chapter 7, Verse 23. ^{10)}

### Archimedes

Archimedes - a famous ancient mathematician, attempted to estimate the value of the number π. By creating more polygons built on the circle and inscribed in the circle. He came to a result that was satisfactory to him after plotting a regular polygon with 96 sides. ^{11)}

### Liu Hui

In the 3rd century AD. Liu Hui began by inscribing a polygon with 192 sides into a circle until he arrived at a polygon that had 3072 sides. This allowed him to determine that the value of Pi is equal to 3, 14159. ^{12)}