The first reference was in 1352
198A.D.
The earliest known textually evidenced approximations of PI date from around 1900 BC. They are found in the Egyptian Rhind Papyrus.
Archimedes (287-212 BC)
Archimedes
The earliest mention of pi comes from over 4000 years ago: the ancient Babylonians calculated the area of a circle by taking 3 times the square of its radius. One Babylonian tablet (ca. 1900-1680 BC) indicates a value of 3.125 for pi.
suck it
-23
762 is when the decimal of pi had the earliest occurrence of the string 999999. Pi has been represented by a Greek letter since the mid 19th century.
The answer will depend on which root.
To find special angle values using reference radians, first identify the angle's reference angle, which is its acute angle equivalent in the first quadrant. For example, for an angle of ( \frac{5\pi}{4} ), the reference angle is ( \frac{\pi}{4} ). Then, use the known sine and cosine values of the reference angle, adjusting for the sign based on the quadrant in which the original angle lies. This method allows you to determine the exact trigonometric values for commonly encountered angles like ( \frac{\pi}{6} ), ( \frac{\pi}{4} ), and ( \frac{\pi}{3} ).
circumference = diameter * pi. Therefore, diameter = circumference ÷ pi.