Roger Arthur Johnson

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Triangle with Johnson circles (red) and Johnson triangle (blue)

Roger Arthur Johnson (born June 9, 1889 in Gardner (Massachusetts) , † 1954 ) was an American mathematician.

Johnson received his bachelor's degree from Amherst College in 1910 and his master's degree from Harvard University the following year . In 1913 he received his doctorate from Harvard under Julian Coolidge ( An Analytic Treatment of the Conic as an Element of Space of Three Dimensions ). Until 1917 he taught mathematics as an instructor at Western Reserve University . He was then a professor at Hamline University . From 1926 he taught mathematics at the branch of Hunter College in Brooklyn , later Brooklyn College. From 1947 until his retirement in 1952 he was in charge of the mathematics department.

He dealt with geometry, especially triangles and circles, about which he wrote a textbook. According to him, Johnson counties named.

He wrote Johnson's sentence:

If three circles of the same size have a common point of intersection, then the circle through the three other points of intersection of two of the three circles is of the same radius as the starting circles. The theorem was proven by Johnson in 1916 and showed that undiscovered theorems also exist in elementary triangular geometry.

Fonts

  • Modern Geometry - An Elementary Treatise on the Geometry of the Triangle and the Circle, Houghton Mifflin, 1929

Web links

Individual evidence

  1. ↑ a b Johnson, Prof. Roger A (rthur). In: James McKeen Cattell , Jacques Cattell: American Men of Science. 5th edition, Science Press, New York 1933.
  2. ↑ The dissertation was published as The Conic as a Space Element , Transactions of the American Mathematical Society, 1914, pp. 335-368
personal data
SURNAME Johnson, Roger Arthur
BRIEF DESCRIPTION American mathematician
DATE OF BIRTH June 9, 1889
PLACE OF BIRTH Gardner (Massachusetts)
DATE OF DEATH 1954