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 is always the same number, no matter which circle you use to compute it. A = pi*r^2 A very brief history of pi. Pi is a very old number. We know that the Egyptians and the Babylonians knew about the existence of the constant ratio pi, although they didn't know its value nearly as well as we do today.ere's pi to many more digits: 3.14159265358979323846. The area of a circle is pi times the square of the length of the radius, or pi r squared: The modern symbol for pi [ ] was first used in our modern sense in 1706 by William Jones, who wrote: