Thereâs really no way to say exact costs for sure but here in the DC area, youâre most likely starting at $5,000-10,000 for a smaller backyard pond and going up from there. One like the pond above â where we brought in literally dozens of truckloads of soil and stone â would be well north of $30,000-40,000.
In 1706 (a fruitful year for Pi), Machin found this rapidly converging formula for its calculation: Ï/4 = 4 x arctan (1/5) - arctan (1/239). Also in 1706, the Welshman, William Jones, became the first person to use the Greek letter Ï as an abbreviation for the periphery of a circle with unit diameter. Euler adopted the symbol, and it quickly became the standard notation for Pi in all mathematical contexts.
Pi, given its name after the Greek letter, was not named so by the Greeks, nor did they invent the concept. It is true that the Ancient Egyptians first discovered the number, and there are references to a number in an Egyptian scroll dating to 1650 BCE.rchimedes approximated it in about 200 BCE in fraction form, since the Greeks did not yet use decimals. He expressed pi as a fraction similar to 3 1/7, which is in decimals approximately 3.14. Mathematicians and scientists left pi at Archimedesâ calculation for centuries.