area of the circle has anything to do with its diameter. The relative area error of works out to about 21 percent, which is much more grave than the approximate lengths in the model circle of the previous section. It is unknown what made Goodwin believe that his rule could be correct. Generally, figures with identical perimeters do not have an identical area (see isoperimetry). The typical demonstration of this fact is to compare a long, thin shape with a small, enclosed area (the area approaching zero as the width decreases) to one with the same perimeter that is approximately as tall as it is wide (the area approaching the square of the width), obviously of a much greater area. Notes References "Indiana's squared circle" by Arthur E. Hallerberg (Mathematics Magazine, vol. 50 (1977), pp. 136–140) gives a good account of the bill. David Singmaster, in "The legal values of pi" (Mathematical Intelligencer, vol. 7 (1985), pp. 69–72) finds seven different values of pi implied in Goodwin's work. Petr Beckmann, A History of π. St. Martin's Press; 1971. External links The Straight Dope – Did a state legislature once pass a law saying pi equals 3? Snopes.com – Alabama’s Slice of Pi: Did the state legislature of Alabama redefine the value of pi according to Biblical precepts? a related hoax Pi Squaring the circle Indiana General Assembly Political history of Indiana Legal history of Indiana 1897 in American law 1897 in Indiana Pseudomathematics