Six Sigma is a set of techniques and tools for process improvement. It was introduced by engineer Bill Smith while working at Motorola in 1986. Jack Welch made it central to his business strategy at General Electric in 1995. Today, it is used in many industrial sectors.
One acre equals 0.0015625 square miles, 4,840 square yards, 43,560 square feet or about 4,047 square metres (0.405 hectares) (see below). While all modern variants of the acre contain 4,840 square yards, there are alternative definitions of a yard, so the exact size of an acre depends on which yard it is based.
There are 43,560 square feet in one acre.   An acre is a unit of area. 640 acres equal a square mile. Hence, it is 1/640 of a square mile. Since a square mile contains 2â¦7,878,400 square feet, an acre is 27,878,400 divided by 640, which is 43,560 square feet. Remember: an acre can be converted to SQUARE feet, not plain (linear) feet. Square feet and feet are not the same units. A foot is unit of distance.