Clark Kimberling (born November 7, 1942, in

Hinsdale, Illinois Hinsdale is a village in DuPage County, Illinois, United States, with a small portion in Cook County, Illinois, Cook County. It is one of the wealthiest communities in Illinois. Hinsdale is a western suburb of Chicago with a population of 17,395 ...

) is a

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, mathematical structure, structure, space, Mathematica ...

, musician, and composer. He has been a mathematics professor since 1970 at the

University of Evansville The University of Evansville (UE) is a private university in Evansville, Indiana. It was founded in 1854 as Carnegie Hall of Moores Hill College, Moores Hill College. The university operates a satellite center, Harlaxton Manor, Harlaxton College ...

. His research interests include

triangle center In geometry, a triangle center or triangle centre is a point in the triangle's plane that is in some sense in the middle of the triangle. For example, the centroid, circumcenter, incenter and orthocenter were familiar to the ancient Greeks, ...

integer sequence In mathematics, an integer sequence is a sequence (i.e., an ordered list) of integers. An integer sequence may be specified ''explicitly'' by giving a formula for its ''n''th term, or ''implicitly'' by giving a relationship between its terms. For ...

s, and hymnology. Kimberling received his PhD in mathematics in 1970 from the

Illinois Institute of Technology The Illinois Institute of Technology, commonly referred to as Illinois Tech and IIT, is a Private university, private research university in Chicago, Illinois, United States. Tracing its history to 1890, the present name was adopted upon the m ...

, under the supervision of Abe Sklar. Since at least 1994, he has maintained a list of triangle centers and their properties. In its current on-line form, the

Encyclopedia of Triangle Centers The Encyclopedia of Triangle Centers (ETC) is an online list of thousands of points or " centers" associated with the geometry of a triangle. This resource is hosted at the University of Evansville The University of Evansville (UE) is a priv ...

, this list comprises tens of thousands of entries. He has contributed to ''The Hymn'', the journal of the Hymn Society in the United States and Canada; and in the '' Canterbury Dictionary of Hymnology''.

Kimberling's golden triangle

Robert C. Schoen has defined a "golden triangle" as a triangle with two of its sides in the

golden ratio In mathematics, two quantities are in the golden ratio if their ratio is the same as the ratio of their summation, sum to the larger of the two quantities. Expressed algebraically, for quantities and with , is in a golden ratio to if \fr ...

. Kimberling has proposed that Schoen's definition of golden triangle be extended to include triangles which have angles that are in the golden ratio. Kimberling has described a "doubly golden triangle" which has two sides that are in golden ratio and which also has two angles that are in golden ratio.Clark Kimberling
"Two Kinds of Golden Triangles, Generalized to Match Continued Fractions"
''Journal for Geometry and Graphics'', Volume 11 (2007), No. 2, pp. 165–171.

References

External links

Kimberling's home page at UE

* Living people 1942 births 20th-century American mathematicians 21st-century American mathematicians American geometers Hymnologists Illinois Institute of Technology alumni American number theorists Musicians from Evansville, Indiana People from Hinsdale, Illinois American recorder players University of Evansville faculty Mathematicians from Illinois {{US-mathematician-stub