# CALCULATIONS OF PI BEFORE COMPUTERS

## CALCULATIONS OF PI BEFORE COMPUTERS

### Babylonians

1600 BC

Babylonians simply made a big circle, and then measured the circumference and diameter with a piece of rope. The Babylonians used this method to find that pi was slightly greater than 3, and came up with the value 3 1/8 or 3.125. Estimating 4 accurate digits of pi

### Ptolemy

150 BC

Gave pi the the value of 3.14166, correct of 4 digits, which he obtained from Archimedes polygonal algorithms.

### Liu Hai

Created a polygon-based algorithm and used this theorem to calculate a 3,072-sided polygon to figure out the value of pi.
Later invented a faster way of calculating pi and the rounded value of 3.14 by using a 96-sided polygon. Knowing that the differences in area of the two polygons, he figured out the polygons made a geometric factor with the number 4. Liu Hai calculated pi to 5 digits - 3.1415

### Zu Chongzhi

Calculated pi equaled around 355/133 by using Hui's algorithm, applying it to a 12,288 sided polygon. With a correct assumption of the first 7 digits of pi in the form of "3.141592920" remained the most accurate approximation of pi for the next 800 plus/minus years to come.

### Jamshid Al - Kashi

Islamic mathematician produced 14 digits of pi using a polygon with 3×2 (to the 28th power) sides.

Indian mathematician discovered the ' Madhavan - Leibniz Series ' a infinite series that calculated pi to 11 decimal places - 3.1415926535

### Ludolph Van Ceulen

German mathematician who is famed for his calculation of π to 35 places. In Germany π used to be called the Ludolphine number.

### Christoph Grienberger

Austrian astronomer Christoph Grienberger arrived at 38 digits, which is the most accurate approximation manually achieved using polygonal algorithms