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.
Square miles to acres area units conversion factor is 640. To find out how many acres in square miles, multiply by the factor or instead, use the converter below. 1 Square Mile = 640 Acres. Square mile and acre are imperial and US customary area units and commonly used for land measurements. In many countries, acre (43560 sq feet) is mostly replaced by hectare (10,000 sq meters) which is a metric area unit. Acre is not officially in use anymore in UK since 2010, but still commonly used in united states.